Glossary A–Z
A clear, structured reference for fastener terminology, materials, thread forms, standards language and general engineering vocabulary. Search by term or synonym, or browse alphabetically using the A–Z navigation.
| Term | Definition |
|---|---|
| # symbol (screw gauge) |
A prefix used in imperial screw sizing to denote gauge numbers such as #6, #8 or #10.
Also known as: gauge symbol Learn more → |
| A2 stainless steel |
An austenitic stainless steel grade offering good corrosion resistance for general environments.
Also known as: 304 stainless Learn more → |
| A4 stainless steel |
A molybdenum‑alloyed stainless steel grade offering enhanced corrosion resistance, especially in marine environments.
Also known as: 316 stainless Learn more → |
| Across‑flats dimension (AF) |
The distance measured between two opposite flat faces of a bolt or nut head, used to determine spanner size.
Also known as: AF size |
| Adjustable fixings |
Fixings that can be positioned or tightened at variable points along a threaded rod to allow precise alignment or adjustment.
Also known as: adjustable assemblies |
| Adjustable fixings (imperial) |
Fixings created using imperial threaded rod that allow components to be positioned or tightened at variable points.
Also known as: adjustable assemblies |
| Adjusting ring |
A ring fitted to a shaft to position, space or secure components axially.
Also known as: shaft adjusting ring |
| Adoption of national thread standards |
The widespread industrial acceptance of a unified thread form across railways, shipyards, machine shops and government departments.
Also known as: national thread adoption Learn more → |
| Aerospace fine‑thread application |
Use of fine‑pitch threads in aircraft and defence equipment where high tensile strength and vibration resistance are essential.
Also known as: aerospace fine thread use |
| Aggregate | The stone or gravel component within concrete that influences drilling behaviour and anchor performance. |
| Agricultural structures |
Timber or metal structures used in farming that commonly use roof bolts or cup square bolts for assembly.
Also known as: farm structures |
| Alignment‑assisted drive |
A drive pattern that helps the tool self‑centre during installation, improving ease of engagement.
Also known as: self‑centering drive |
| All-metal locking nut |
A nut that provides vibration resistance through deformed threads or elliptical geometry rather than nylon inserts.
Also known as: prevailing torque nut |
| Alloying elements |
Chemical elements added to steel to modify strength, hardenability, corrosion resistance or toughness.
Also known as: steel alloy additions |
| Allthread |
A fully threaded rod used for bracing, suspending, joining and general construction applications.
Also known as: threaded rod, studding Learn more → |
| Allthread (imperial) |
A fully threaded rod using imperial thread forms such as Whitworth, UNC, UNF and BA.
Also known as: imperial threaded rod, studding Learn more → |
| Allthread length |
The overall length of a fully threaded rod, measured end‑to‑end.
Also known as: threaded rod length Learn more → |
| All‑metal prevailing‑torque nut |
A lock nut that generates frictional resistance through deformed metal sections rather than polymer inserts.
Also known as: metal lock nut |
| Anchor bolt |
A bolt designed to secure structural elements to concrete, typically using cast‑in or post‑installed anchoring methods.
Also known as: foundation bolt, concrete anchor bolt |
| Anchoring sleeve expansion |
The radial expansion of the EPDM sleeve around the TIGER tie when the screw is tightened, creating a secure mechanical grip in masonry.
Also known as: expanding sleeve action |
| Anchoring systems |
Systems that use threaded rod in conjunction with anchors or resin to secure components into concrete or masonry.
Also known as: anchor assemblies |
| Anglo‑American‑Canadian Agreement (1948) |
The post‑war agreement between the UK, USA and Canada that established the Unified Thread Standard, including UNC and UNF.
Also known as: 1948 Unified Thread Agreement Learn more → |
| Annealing |
A heat treatment process that softens metal, improves ductility and relieves internal stresses.
Also known as: metal softening, stress relief heat treatment Learn more → |
| Anti‑corrosion coating |
A protective layer applied to fasteners to reduce oxidation and extend service life.
Also known as: corrosion‑resistant coating, protective coating Learn more → |
| Anti‑vibration washer |
A washer designed to reduce loosening caused by vibration or dynamic loads.
Also known as: vibration‑resistant washer, locking washer |
| Appearance‑critical fastening |
Fastening applications where the visible head of the screw or bolt must provide a neat, decorative or unobtrusive finish.
Also known as: visible fixings, decorative fastening |
| Appliances (machine screws) |
Equipment and devices assembled using machine screws to secure panels, brackets and internal components.
Also known as: electrical appliances |
| Applications (construction) |
Typical uses for threaded rod including bracing, suspending services, joining components and general engineering.
Also known as: use cases |
| Applications (heritage engineering) |
Uses of imperial threaded rod in restoration, maintenance and legacy machinery.
Also known as: heritage applications |
| Assembling enclosures |
Using machine screws to secure covers, housings or casings in electrical or mechanical equipment.
Also known as: enclosure assembly |
| Assembly torque |
The torque applied during installation to achieve the desired preload in a bolted joint.
Also known as: installation torque, tightening torque |
| Austenitic stainless steel |
A corrosion‑resistant stainless steel family containing chromium and nickel, used for A2 and A4 fastener grades.
Also known as: A2 stainless, A4 stainless, austenitic grade, 300-series stainless Learn more → |
| Austenitising temperature |
The high temperature at which steel is heated during heat treatment to form austenite before quenching.
Also known as: austenite formation temperature Learn more → |
| Automotive fine‑thread application |
Use of finer‑pitch threads in engines, gearboxes and suspension components to improve strength and vibration resistance.
Also known as: automotive fine thread use |
| Automotive repairs (bolts) |
Maintenance and repair tasks on vehicles that require high‑strength bolts such as socket cap screws or hexagon bolts.
Also known as: vehicle repairs |
| Automotive restoration |
The repair or rebuilding of classic vehicles using original imperial fasteners such as Whitworth, UNC, UNF and BSF.
Also known as: classic car restoration |
| Automotive zinc flake standard |
The widespread use of zinc flake coatings in the automotive industry due to their high corrosion resistance and suitability for high-strength fasteners.
Also known as: automotive zinc flake requirement Learn more → |
| Auto‑feed driver bit |
A screwdriver bit designed for use in collated screw guns, providing continuous screw feeding for rapid installation.
Also known as: collated driver bit, autofeed bit Learn more → |
| Axial load distribution |
The spreading of clamping force along the axis of a fastener, improved by using washers.
Also known as: axial load spread |
| BA geometric progression |
The mathematical basis of the BA thread system, where sizes follow a logarithmic progression rather than direct diameter measurements.
Also known as: BA size progression Learn more → |
| BA thread |
A fine, miniature imperial thread form used in instrumentation, electrical work and precision assemblies.
Also known as: British Association thread Learn more → |
| BA thread system |
A metric‑derived miniature thread system introduced in 1903 for precision instruments, electrical equipment and fine mechanical assemblies.
Also known as: British Association thread Learn more → |
| Ball knob |
A spherical operating knob used on levers, clamping devices and machine controls.
Also known as: round knob |
| Barrel nut |
A cylindrical internally threaded nut used in furniture, structural joints and applications requiring a cross‑bolt connection.
Also known as: cross dowel, connector nut |
| Bar‑operated screw |
A screw with radial holes in the head allowing adjustment using a bar or pin for fine positioning.
Also known as: capstan screw |
| Bearing surface (head) |
The underside of a fastener head that contacts the material and distributes clamping load.
Also known as: head bearing face |
| Bearing surface (nut) |
The underside surface of a nut that contacts the clamped material or washer.
Also known as: nut bearing face Learn more → |
| Bearing surface (washer) |
The flat surface of a washer that contacts the fastened material and spreads load.
Also known as: washer bearing face Learn more → |
| Bearing‑surface consistency |
The ability of a washer to provide a smooth, uniform surface under the fastener head or nut, improving tightening accuracy.
Also known as: consistent bearing surface |
| Belleville washer |
A conical spring washer used to maintain tension and compensate for thermal expansion.
Also known as: conical spring washer |
| Black oxide finish |
A thin conversion coating applied to steel fasteners to provide mild corrosion resistance and a non‑reflective black appearance.
Also known as: blackened finish Learn more → |
| Black zinc passivate |
A dark trivalent chromium passivation layer applied over zinc plating for decorative or low‑glare applications.
Also known as: black passivate Learn more → |
| Blind rivet |
A rivet that can be installed from one side only using a mandrel that expands the rivet body to form a joint.
Also known as: pop rivet |
| Bolt grade |
A numerical strength designation indicating the tensile and yield properties of a bolt.
Also known as: bolt strength class Learn more → |
| Bolt head styles |
The various head shapes used on bolts, each providing different load distribution, tool engagement and clearance characteristics.
Also known as: bolt head types Learn more → |
| Bolt length |
The measurement from the underside of the bolt head to the end of the shank.
Also known as: fastener length Learn more → |
| Bonding (electrical) |
The process of electrically connecting metal components to ensure continuity and safe fault paths.
Also known as: electrical bonding Learn more → |
| Bracing |
Using threaded rod or other components to provide structural support or stabilisation.
Also known as: structural bracing Learn more → |
| Bracing assemblies (imperial) |
Structural or support assemblies formed using imperial threaded rod and associated components.
Also known as: bracing systems |
| Bracket installation |
Using bolts to secure brackets to structural members, machinery or assemblies.
Also known as: bracket mounting |
| Bracket mounting |
Using machine screws to secure brackets to panels, frames or equipment.
Also known as: mounting brackets |
| Brackets |
Support components used with threaded rod for suspending or fixing services.
Also known as: mounting brackets |
| Brackets (imperial) |
Support components used with imperial threaded rod for suspending or fixing equipment.
Also known as: mounting brackets |
| Brake‑lining rivet |
A rivet designed for fastening brake linings and clutch linings in automotive and industrial applications.
Also known as: clutch‑lining rivet |
| Brass | A copper‑zinc alloy used for threaded rod where corrosion resistance and appearance are important. Learn more → |
| Brass machine screws |
Machine screws manufactured from brass for corrosion resistance and electrical compatibility.
Also known as: brass fasteners Learn more → |
| Brass nut |
A nut made from brass, offering corrosion resistance, electrical conductivity and a decorative finish.
Also known as: brass hex nut Learn more → |
| Breakaway torque |
The torque required to initiate movement of a tightened fastener after static friction has been established.
Also known as: break-loose torque |
| Bright zinc plating |
A protective zinc coating applied to steel threaded rod to improve resistance to light corrosion.
Also known as: BZP, zinc plated Learn more → |
| Bright zinc plating (BZP) |
A shiny electroplated zinc finish that provides light corrosion protection and a clean, reflective appearance.
Also known as: BZP, bright zinc plate Learn more → |
| BS (British Standard) |
The UK’s national standards system, historically responsible for defining thread forms such as BSW, BSF and BA.
Also known as: British Standards Institution, BSI standard Learn more → |
| BSF thread |
A fine‑pitch British Standard thread form used in older machinery and engineering applications.
Also known as: British Standard Fine Learn more → |
| BSF thread system |
A fine‑pitch British thread system using Whitworth geometry, developed for stronger and more vibration‑resistant fastening.
Also known as: British Standard Fine Learn more → |
| BSW nuts |
Nuts manufactured to the British Standard Whitworth thread form for use with BSW threaded rod.
Also known as: Whitworth nuts Learn more → |
| BSW thread |
A coarse‑pitch British Standard thread form commonly known as Whitworth.
Also known as: Whitworth, British Standard Whitworth Learn more → |
| BSW thread system |
The coarse‑pitch British Standard Whitworth thread series derived from Whitworth’s 1841 geometry.
Also known as: British Standard Whitworth Learn more → |
| Build‑to‑existing connection |
The structural connection formed when new masonry is tied into an existing wall using mechanical starter ties.
Also known as: new‑to‑existing wall connection |
| Bulk OEM driver bits |
Unpackaged driver bits supplied in manufacturer OEM bags, typically in quantities of 100 for high‑volume professional users.
Also known as: OEM bulk bits Learn more → |
| Bulk OEM supply (Senco) |
Unpackaged bulk quantities of 100 HELFAST driver bits supplied in OEM bags for Senco DS‑series tools.
Also known as: Senco OEM bulk bits Learn more → |
| BZP |
Abbreviation for Bright Zinc Plated, referring to a reflective electroplated zinc finish used on steel fasteners.
Also known as: bright zinc plated Learn more → |
| Cable management systems |
Systems used to support and route electrical cables, often suspended using threaded rod.
Also known as: cable trays, cable ladders |
| Cable trays (imperial installations) |
Support systems for electrical cables, often suspended using imperial threaded rod.
Also known as: cable management trays |
| Cam‑out resistance |
The ability of a driver bit to maintain engagement with the screw recess under torque without slipping out.
Also known as: anti‑cam‑out performance Learn more → |
| Cam‑out tendency |
The likelihood of a driver slipping out of the recess under torque, especially with slotted drives.
Also known as: drive slippage |
| Cap nut |
A nut with a closed end that protects exposed bolt threads and improves appearance.
Also known as: acorn nut, dome nut |
| Capstan screw |
A screw with a cylindrical head and radial holes for bar tightening, used for precision adjustment.
Also known as: bar‑operated screw |
| Carbon content |
The percentage of carbon in steel, which strongly influences hardness, strength and heat-treatment response.
Also known as: steel carbon level Learn more → |
| Carbon steel |
Steel containing primarily iron and carbon, used for general‑purpose fasteners and high‑strength property classes.
Also known as: plain carbon steel Learn more → |
| Carriage bolt |
A bolt with a domed head and square neck, commonly used in timber construction and joinery.
Also known as: cup square bolt Learn more → |
| Castle nut |
A slotted nut designed for use with a split pin to prevent loosening under vibration.
Also known as: castellated nut |
| Cathodic protection |
A corrosion‑control method where a metal surface is made the cathode of an electrochemical cell.
Also known as: sacrificial protection Learn more → |
| Cavity wall tie (mechanical type) |
A mechanical fixing used to connect the inner and outer leaves of a cavity wall, providing structural stability and load transfer.
Also known as: mechanical cavity tie Learn more → |
| Cavity wall tie (universal type) |
A mechanical tie designed to connect the inner and outer leaves of a cavity wall, suitable for a range of cavity widths.
Also known as: universal cavity tie Learn more → |
| Cavity‑span requirement |
The need for a cavity wall tie to bridge the full cavity width while providing secure embedment into both masonry leaves.
Also known as: cavity span rule Learn more → |
| Chamfered washer |
A washer with a bevelled outer edge, providing a neater appearance and reduced edge interference.
Also known as: bevelled washer Learn more → |
| Chamfer‑point grooved pin |
A grooved pin with a chamfered end to ease insertion and improve alignment during press‑fit assembly.
Also known as: chamfered grooved pin |
| Cheese head screw |
A cylindrical, high‑profile head used on machine screws, typically with a slot drive.
Also known as: cheese head Learn more → |
| Chemical exposure | Environmental conditions involving chemicals that influence material selection for threaded rod. Learn more → |
| Chloride resistance |
A material’s ability to resist corrosion caused by chloride ions, especially in marine or chemical environments.
Also known as: salt resistance Learn more → |
| Chrome 6 (hexavalent chromium) |
A form of chromium historically used in zinc passivation layers but now restricted due to environmental and health concerns.
Also known as: hexavalent chrome, Cr6 Learn more → |
| Chrome 6–free passivation |
A modern zinc passivation system using trivalent chromium to provide corrosion protection without hazardous hexavalent compounds.
Also known as: trivalent passivation Learn more → |
| Circlip |
A spring-steel retaining ring fitted into a groove to provide axial retention on shafts or in bores.
Also known as: snap ring, retaining ring |
| Clamp load |
The tension created in a bolt when tightened, which clamps the joint members together.
Also known as: joint clamp load, bolt tension |
| Clamping force |
The compressive force generated when a bolt is tightened, holding components securely together.
Also known as: bolt preload |
| Clamping force (nut) |
The compressive force generated when a nut is tightened onto a bolt or threaded rod.
Also known as: bolt preload |
| Clamping force capacity |
The maximum preload a fastener can generate based on its strength class and heat-treated properties.
Also known as: preload capacity |
| Clamping handle |
A handle used to apply manual clamping force in fixtures, jigs and machine assemblies.
Also known as: operating handle |
| Clamping performance |
The effectiveness of a nut and bolt in generating and maintaining joint tension under load.
Also known as: joint clamping performance |
| Clean appearance (bolts) |
A bright, tidy visual finish achieved using zinc plated or domed‑head bolts.
Also known as: tidy finish |
| Clear zinc passivate |
A transparent trivalent chromium passivation layer applied over zinc plating to enhance corrosion resistance.
Also known as: clear passivate, blue passivate Learn more → |
| Clevis pin |
A headed pin used with a cotter or split pin to form a pivot or linkage joint.
Also known as: linkage pin |
| Clevis pin washer |
A washer used with clevis pins to provide proper bearing surface and axial retention in linkage assemblies.
Also known as: clevis washer |
| Closed‑end blind rivet |
A blind rivet with a sealed end that prevents leakage and provides higher shear strength.
Also known as: sealed blind rivet |
| Close‑tolerance bolt |
A precision bolt with a tightly controlled shank diameter designed to fit accurately into reamed holes for high‑accuracy assemblies.
Also known as: precision‑fit bolt |
| Coarse thread (metric) |
The standard metric thread pitch series used for general‑purpose fasteners.
Also known as: metric coarse thread |
| Coarse thread series (imperial) |
Imperial thread series with larger pitch, such as Whitworth and UNC.
Also known as: coarse imperial threads |
| Coarse‑pitch Unified thread |
A thread in the Unified system with larger pitch for strength, durability and rapid assembly, represented by the UNC series.
Also known as: UNC coarse thread |
| Coastal installations |
Applications located near the sea where high chloride levels require corrosion‑resistant materials.
Also known as: marine environments |
| Coating thickness |
The measured thickness of a protective coating applied to a fastener, affecting corrosion resistance and thread fit.
Also known as: plating thickness Learn more → |
| Cold‑formed fastener |
A fastener manufactured by deforming metal at room temperature to improve strength and grain flow.
Also known as: cold‑headed fastener |
| Cold‑rolled thread |
A thread formed by rolling rather than cutting, producing superior surface finish and fatigue strength.
Also known as: rolled thread |
| Collar plug |
A pipe plug with an external hex head and collar used for sealing threaded ports.
Also known as: hex collar plug |
| Collated screw system (Makita 6833‑series) |
The auto‑feed mechanism used in Makita 6833, 6836 and 6835DWD screwdrivers, requiring precise bit length and diameter for correct feed timing.
Also known as: Makita 6833‑series collated system Learn more → |
| Collated screw system (Makita) |
The auto‑feed mechanism used in Makita 6830 and 6831 screwdrivers, requiring precise bit length and diameter for correct feed timing.
Also known as: Makita collated system Learn more → |
| Collated screw system (Senco DS‑series) |
The auto‑feed mechanism used in Senco DS212, DS215, DS232, DS235, DS5525 and DS5550 screwdrivers, requiring precise bit length and diameter.
Also known as: Senco DS collated system Learn more → |
| Collated screw system compatibility |
The ability of a driver bit to operate correctly within an auto‑feed collated screw gun such as the Hilti SMD 57.
Also known as: auto‑feed system compatibility Learn more → |
| Compact assembly |
An assembly where space around the fastener head is limited, requiring internal‑drive head styles such as socket cap screws.
Also known as: restricted access assembly |
| Compatible early metric systems |
The pre‑ISO metric thread forms developed in France, Switzerland and Germany that shared 60° geometry but differed in details.
Also known as: pre‑ISO European metric threads Learn more → |
| Concrete–brick–block compatibility |
The ability of a fixing system to achieve reliable anchorage across common masonry substrates including concrete, brick and block.
Also known as: masonry substrate compatibility Learn more → |
| Constant‑pitch thread series |
A thread series in which all diameters share the same pitch, used in the Unified UN series.
Also known as: UN constant‑pitch series |
| Construction applications |
Uses of threaded rod in building, structural work and service installation.
Also known as: building applications |
| Core fastener characteristics |
The fundamental features that define a fastener: head style, drive type, material, dimensions and finish.
Also known as: fastener attributes Learn more → |
| Corrosion fatigue |
The reduction in fatigue strength caused by simultaneous cyclic loading and corrosive environment.
Also known as: fatigue‑corrosion interaction Learn more → |
| Corrosion resistance (machine screws) |
The ability of machine screw materials such as stainless steel or brass to resist corrosion.
Also known as: corrosion performance Learn more → |
| Corrosion‑resistance grade |
A classification defining the corrosion performance of stainless steel fasteners, such as A1–A5.
Also known as: stainless grade Learn more → |
| Countersunk head |
A conical screw head designed to sit flush with the surface when installed.
Also known as: CSK head Learn more → |
| Countersunk Pozi |
A countersunk machine screw with a Pozi drive for improved torque transfer.
Also known as: CSK Pozi Learn more → |
| Countersunk rivet |
A rivet with a flat, angled head designed to sit flush with the material surface.
Also known as: csk rivet |
| Countersunk seating |
A flush installation where the head sits level with or below the surface using a conical recess.
Also known as: flush seating |
| Countersunk slot |
A countersunk machine screw with a traditional slotted drive.
Also known as: CSK slot Learn more → |
| Countersunk socket screw |
A screw with a countersunk head and internal hex drive for flush installation.
Also known as: csk socket screw |
| Countersunk square‑neck bolt |
A bolt with a countersunk head and square neck that locks into timber or metal to prevent rotation during tightening.
Also known as: csk square‑neck bolt |
| Countersunk tapping screw |
A self‑tapping screw with a countersunk head designed to sit flush with the material surface.
Also known as: csk tapping screw |
| Countersunk toothed washer |
A toothed lock washer with a countersunk profile for use with countersunk screws.
Also known as: csk serrated washer |
| Counter‑intuitive thread sizing |
A sizing convention where larger numerical designations correspond to smaller fasteners, as seen in the BA thread system.
Also known as: reverse size numbering |
| Coupler |
A long nut used to join two lengths of threaded rod together.
Also known as: coupling nut |
| Couplers (imperial) |
Long nuts used to join two lengths of imperial threaded rod.
Also known as: coupling nut |
| Coupling nut |
A long hexagon nut used to join two threaded rods or studs.
Also known as: extension nut |
| Crest radius (Whitworth) |
The rounded crest geometry of Whitworth threads, defined as 0.1373 × pitch.
Also known as: Whitworth crest rounding |
| Crest truncation |
The intentional flattening or rounding of the thread crest to improve fit and reduce stress concentration.
Also known as: thread crest truncation |
| Crests (thread geometry) |
The top surfaces of thread profiles, rounded in Whitworth threads for improved strength and manufacturability.
Also known as: thread crests |
| Cross‑industry compatibility | The ability for fasteners and threaded components to be used across different industries due to shared standards and dimensions. |
| Cross‑recessed tapping screw |
A self‑tapping screw with a cross‑shaped drive for improved torque transfer and reduced cam‑out.
Also known as: Pozi tapping screw, Phillips tapping screw |
| Cross‑slot drive |
A two‑slot drive pattern offering improved tool engagement and easier alignment compared with a single slot.
Also known as: cross recess Learn more → |
| Cross‑standard fine‑thread incompatibility |
The lack of interchangeability between British BSF and American NF fine‑pitch threads before the Unified system.
Also known as: pre‑Unified fine‑thread incompatibility |
| Cross‑system incompatibility (pre‑1948) |
The lack of interchangeability between British Whitworth threads and American NC/NF threads before the Unified system.
Also known as: pre‑Unified incompatibility |
| Crown nut |
A nut with castellations used with a split pin to prevent loosening.
Also known as: castle nut |
| Cup square bolt |
A bolt with a domed head and square neck, commonly known as a carriage bolt.
Also known as: carriage bolt Learn more → |
| Cup‑point set screw |
A set screw with a concave tip that bites into the surface for high holding power.
Also known as: cup point screw |
| Cut thread |
A thread produced by machining material away rather than deforming it.
Also known as: machined thread |
| Cut‑tip driver bit |
A driver bit with a precision‑machined cut tip that provides superior fit, torque transfer and reduced cam‑out compared with forged tips.
Also known as: precision cut tip, machined tip Learn more → |
| Deburring |
The removal of sharp edges or burrs after machining or cutting to improve safety and fit.
Also known as: burr removal |
| Decimal‑based thread designation |
A metric naming system where diameters and pitches are expressed in millimetres, such as M8 × 1.25.
Also known as: metric decimal designation Learn more → |
| Decorative finish |
A finish chosen for its visual appearance as well as functional performance, common on raised countersunk screws.
Also known as: aesthetic finish Learn more → |
| Decorative head profile |
A head shape chosen for its visual appearance as well as function, such as raised countersunk or round heads.
Also known as: aesthetic head profile Learn more → |
| Dedicated starter tie |
A TIGER tie designed solely for starter applications, available in a 25 mm length.
Also known as: starter‑only tie Learn more → |
| Deformation limit |
The stress level at which a fastener begins to deform permanently, defined by its yield strength.
Also known as: yield point Learn more → |
| Deformed thread nut |
A locking nut with intentionally distorted threads to create friction and resist loosening.
Also known as: distorted thread nut |
| Dependable load distribution |
The even spreading of clamping force across components when bolts are tightened correctly.
Also known as: reliable load distribution |
| Derived diameter (BA) |
The BA major diameter calculated from pitch using the formula d = 6 × pitch^1.2.
Also known as: BA diameter formula Learn more → |
| Diameter × Length expression |
The standard way of specifying fastener size, combining nominal diameter and length into a single designation.
Also known as: size expression Learn more → |
| Diamond‑groove pin |
A grooved pin with diamond‑shaped grooves providing strong interference‑fit retention.
Also known as: diamond‑pattern grooved pin |
| Differential thermal expansion |
The difference in expansion rates between materials when heated, affecting preload in bolted joints.
Also known as: thermal expansion mismatch |
| Dimensional data |
Technical measurements including head diameter, height, thread length and tolerances for machine screws.
Also known as: dimensions Learn more → |
| DIN (Deutsches Institut für Normung) |
The German national standards organisation responsible for publishing engineering and fastener standards used worldwide.
Also known as: German Institute for Standardisation Learn more → |
| DIN EN |
The German national publication of a European (EN) standard, indicating that the EN specification has been adopted into the German DIN catalogue.
Also known as: German EN standard Learn more → |
| DIN EN ISO |
A designation indicating that an ISO standard has been adopted as a European (EN) standard and then published nationally in Germany under the DIN catalogue.
Also known as: German EN ISO standard Learn more → |
| Disc spring |
A washer‑like spring element used to maintain preload in bolted joints.
Also known as: Belleville disc spring, Belleville washer |
| Dog‑point set screw |
A set screw with a cylindrical tip used for axial positioning without damaging the mating surface.
Also known as: dog point screw |
| Double shear |
A loading condition where a fastener is subjected to shear across two planes, increasing load capacity.
Also known as: two‑plane shear |
| Double‑end stud |
A stud with threads at both ends and an unthreaded shank in the middle, used for bolted joints where components must be clamped between nuts.
Also known as: double‑ended stud |
| Dowel pin |
A cylindrical pin used for accurate alignment, location and repeatable positioning in mechanical assemblies.
Also known as: parallel dowel pin |
| Drip ring (EPDM) |
A raised EPDM feature on a cavity wall tie that prevents moisture from tracking across the cavity from one leaf to the other.
Also known as: EPDM moisture drip Learn more → |
| Drive engagement |
The quality of contact between the driver and the recess, affecting torque transfer and slippage resistance.
Also known as: driver engagement Learn more → |
| Drive recess depth |
The depth of the screw’s drive recess, affecting tool engagement, torque transfer and cam‑out resistance.
Also known as: recess depth Learn more → |
| Drive type |
The recess or interface used to apply torque to a machine screw, such as slot or Pozi.
Also known as: screw drive Learn more → |
| Drive wear |
Progressive rounding or deformation of the screw recess caused by repeated installation cycles.
Also known as: recess wear |
| Drive wobble |
Side‑to‑side movement of the driver bit within the screw recess, reducing torque efficiency and increasing wear.
Also known as: bit wobble |
| Driver bit diameter |
The shaft diameter of a driver bit, which must match the auto‑feed tool’s guide channel for correct operation.
Also known as: bit shaft diameter Learn more → |
| Driver bit diameter (5 mm) |
The 5 mm shaft diameter required for correct alignment and feed operation in Makita 6833, 6836 and 6835DWD auto‑feed screwdrivers.
Also known as: 5 mm bit diameter Learn more → |
| Driver bit diameter (6 mm – Senco) |
The 6 mm shaft diameter required for correct alignment and feed operation in Senco DS‑series auto‑feed screwdrivers.
Also known as: 6 mm Senco bit diameter Learn more → |
| Driver bit diameter (6 mm) |
The 6 mm shaft diameter required for correct alignment and feed operation in Makita 6830 / 6831 auto‑feed screwdrivers.
Also known as: 6 mm bit diameter Learn more → |
| Driver slip |
Loss of engagement between the screwdriver and the screw drive, often occurring with slotted drives under high torque.
Also known as: cam-out Learn more → |
| Dry lubrication coating |
A low‑friction surface treatment such as MoS₂ or PTFE used to reduce torque scatter in bolted joints.
Also known as: dry lube coating Learn more → |
| Dual‑thread stud |
A stud with two threaded ends used to secure components between nuts or into tapped holes.
Also known as: two‑ended stud |
| Ductility |
A material’s ability to deform plastically without breaking, essential for absorbing shock and preventing brittle failure.
Also known as: plastic deformation capacity Learn more → |
| Ducting |
HVAC components used to distribute air, commonly suspended using threaded rod.
Also known as: air ducts |
| Ducting (imperial installations) |
HVAC ductwork commonly suspended using imperial threaded rod in restoration or legacy systems.
Also known as: air ducting |
| Dynamic loading |
Loading that varies over time due to vibration, shock or cyclic forces.
Also known as: cyclic loading |
| Early European metric standardisation |
The 19th‑century development of national metric thread forms in France, Switzerland and Germany.
Also known as: pre‑ISO metric development Learn more → |
| Early industrial threadmaking |
The pre‑standardisation period when workshops cut threads to their own patterns, preventing interchangeability.
Also known as: pre‑standard threadmaking Learn more → |
| Edge chamfer |
A bevel applied to the end of a bolt or screw to ease insertion and protect threads.
Also known as: thread chamfer |
| Edge distance |
The minimum distance required between a fastener hole and the edge of a material to prevent cracking or pull-out.
Also known as: minimum edge spacing |
| Elastic deformation |
Reversible deformation that occurs when a fastener is loaded within its elastic limit.
Also known as: elastic strain |
| Elastic limit |
The maximum stress a material can withstand without permanent deformation.
Also known as: proportional limit |
| Electrical assemblies (machine screws) |
Electrical components and housings assembled using machine screws for secure, serviceable fixings.
Also known as: electrical equipment assembly |
| Electroplating |
A coating process that uses electrical current to deposit metal onto a fastener surface.
Also known as: electrodeposition Learn more → |
| Electro‑galvanising |
A zinc coating applied by electroplating to provide corrosion protection and a bright finish.
Also known as: electro‑zinc plating Learn more → |
| Embedment depth (dual‑leaf) |
The minimum depth a cavity tie must penetrate into each masonry leaf to achieve secure anchorage.
Also known as: dual‑leaf embedment Learn more → |
| Embrittlement |
A loss of ductility in a material, making it more prone to cracking under load.
Also known as: material embrittlement Learn more → |
| EN (European Standard) |
A standard developed by the European Committee for Standardization (CEN) and adopted across EU and EFTA member states.
Also known as: CEN standard, European Norm Learn more → |
| End‑of‑line marking |
Identification marks applied to fasteners to indicate grade, manufacturer or batch.
Also known as: fastener marking |
| Engineering standardisation |
The process of defining common thread forms, pitches and diameters to ensure interchangeability of components.
Also known as: thread standardisation Learn more → |
| Engineering standardisation (Whitworth era) |
The shift from workshop‑specific thread forms to a unified national standard introduced by Whitworth in 1841.
Also known as: Whitworth standardisation Learn more → |
| Enhanced‑retention grooved pin |
A grooved pin with modified groove geometry designed to provide superior radial expansion and retention.
Also known as: high‑retention grooved pin |
| Environmental requirements (fasteners) |
Conditions such as moisture, chemicals, temperature and atmospheric exposure that influence the correct material and finish selection for fasteners.
Also known as: environmental conditions, environmental factors Learn more → |
| EPDM expansion sleeve |
A flexible EPDM rubber sheath that expands radially when the TIGER tie screw is tightened, gripping the surrounding masonry.
Also known as: EPDM anchoring sleeve Learn more → |
| Equal‑thread stud |
A double‑end stud with identical thread lengths on both ends for balanced engagement.
Also known as: equal‑length stud |
| Equipment assembly (bolts) |
Using bolts to assemble machinery, tools or mechanical systems.
Also known as: equipment build |
| Equipment mounting |
Using bolts to secure machinery, fixtures or components to frames, bases or structures.
Also known as: equipment fixing |
| Ergonomic handle |
A handle shaped to improve comfort and reduce fatigue during manual operation.
Also known as: ergonomic operating handle |
| Expanding sealing cap |
A cap that expands to seal or close an opening in mechanical or structural assemblies.
Also known as: expanding cap |
| Expansion anchor |
A mechanical anchor that expands within a drilled hole to create frictional or mechanical interlock.
Also known as: expanding anchor |
| External retaining ring |
A retaining ring fitted into a groove on the outside of a shaft to prevent axial movement of components.
Also known as: external circlip |
| External‑thread taper pin |
A taper pin with an external thread used for axial extraction and secure positioning.
Also known as: threaded taper pin |
| External‑tooth lock washer |
A lock washer with serrations on the outer edge that bite into the mating surface to resist loosening.
Also known as: external serrated washer |
| Fabrication | The process of assembling or modifying components using threaded rod and associated hardware. |
| Fabrication (bolts) |
The assembly of metal structures using bolts for alignment, clamping and joining.
Also known as: metal fabrication |
| Fastener labelling |
The required markings and packaging information used to identify fastener grade, manufacturer and traceability.
Also known as: fastener marking and labelling |
| Fastener marking |
Permanent markings applied to fasteners to indicate property class, manufacturer and specification compliance.
Also known as: head marking |
| Fastener preload |
The tension generated in a fastener when tightened, which clamps the joint members together.
Also known as: bolt preload, joint preload |
| Fastening clamp |
A U‑shaped clamp used to secure components in mechanical assemblies.
Also known as: U‑clamp |
| Fatigue resistance |
A fastener’s ability to withstand repeated cyclic loading without cracking or failure.
Also known as: fatigue strength |
| Feather key |
A parallel key used to transmit torque between a shaft and hub while allowing axial movement.
Also known as: parallel feather key |
| Feature‑based fastener classification |
A method of identifying fasteners by analysing their head style, drive type, material, dimensions and finish.
Also known as: fastener feature grouping Learn more → |
| Fencing panels |
Timber or composite panels secured using cup square bolts for strong, rotation‑resistant fixing.
Also known as: fence panels |
| Fine adjustment (imperial) |
Precise positioning or tuning enabled by fine‑pitch imperial threads such as UNF or BA.
Also known as: precision adjustment |
| Fine mechanical assembly |
A mechanism requiring miniature, precise threaded fasteners such as those defined by the BA system.
Also known as: precision mechanical assembly |
| Fine pitch metric thread |
A metric thread with a smaller pitch than the standard coarse series, offering finer adjustment and improved vibration resistance.
Also known as: metric fine thread Learn more → |
| Fine thread series (imperial) |
Imperial thread series with smaller pitch, such as UNF and BSF.
Also known as: fine imperial threads Learn more → |
| Finer adjustment capability |
The ability of a fine‑pitch thread to allow more precise axial movement per turn.
Also known as: fine adjustment |
| Fine‑pitch bolt |
A bolt with a smaller thread pitch than the coarse series, providing finer adjustment and improved vibration resistance.
Also known as: metric fine bolt Learn more → |
| Fine‑pitch nut |
A nut with a fine‑pitch thread for improved preload control and vibration resistance.
Also known as: metric fine nut |
| Fine‑pitch socket screw |
A socket head cap screw with a fine‑pitch metric thread for improved adjustment accuracy and vibration resistance.
Also known as: metric fine socket screw Learn more → |
| Fine‑pitch thread |
A thread with a smaller pitch than the coarse series, providing finer adjustment and greater tensile stress area.
Also known as: fine thread Learn more → |
| Fine‑pitch Unified thread |
The fine‑pitch series of the Unified Thread Standard, offering greater tensile strength and precision than UNC.
Also known as: UNF thread Learn more → |
| Fine‑pitch Whitworth thread |
A thread form using Whitworth’s 55° geometry but with reduced pitch for greater strength and precision.
Also known as: fine Whitworth form Learn more → |
| Fine‑thread‑forming screw |
A thread‑forming screw with a fine‑pitch metric thread for improved engagement in ductile metals.
Also known as: fine‑pitch forming screw |
| Finish suitability |
The compatibility of a coating with different fastener strength classes based on hydrogen risk, thread fit and durability.
Also known as: coating suitability Learn more → |
| Fit bolt |
A bolt with a controlled shank diameter designed to fit closely in structural steelwork holes, improving shear capacity.
Also known as: close‑fit bolt Learn more → |
| Fit classes (imperial threads) |
Tolerance classes defining how tightly internal and external imperial threads fit together.
Also known as: thread fit Learn more → |
| Fixing components to threaded plates |
Using machine screws to secure parts to plates with pre‑tapped holes.
Also known as: threaded plate fixing |
| Fixtures (bolts) |
Components such as brackets, plates or hardware secured using bolts.
Also known as: hardware fixtures Learn more → |
| Fixtures (machine screws) |
Components such as fittings, plates or hardware secured using machine screws.
Also known as: hardware fixtures Learn more → |
| Flange bolt |
A bolt with an integrated washer‑like flange under the head to distribute load and reduce the need for a separate washer.
Also known as: washer‑flanged bolt |
| Flange lock nut |
A flange nut incorporating a locking feature to resist loosening under vibration.
Also known as: locking flange nut |
| Flange nut |
A nut with an integrated washer-like flange to increase bearing area and reduce the need for a separate washer.
Also known as: washer-faced nut, integral‑flange nut |
| Flat countersunk rivet |
A solid rivet with a flat countersunk head for flush installation in sheet metal.
Also known as: flat csk rivet |
| Flat round head rivet |
A solid rivet with a low‑profile round head for general fastening in sheet metal and light structures.
Also known as: low round head rivet |
| Flat washer |
A flat disc used to distribute load under a bolt head or nut and protect the material surface.
Also known as: plain washer Learn more → |
| Flat width before rounding (Whitworth) |
The theoretical flat at the crest and root of a Whitworth thread before radiusing, equal to 0.6403 × pitch.
Also known as: Whitworth flat width Learn more → |
| Flat‑crest thread form |
A thread geometry where the crest is truncated flat rather than rounded, characteristic of Unified threads.
Also known as: flat‑topped thread |
| Flat‑root Unified geometry |
A thread form with flat crests and roots, used across all Unified series including UNF.
Also known as: Unified flat‑root form Learn more → |
| Floating nut plate |
A nut mounted in a cage or plate that allows slight movement for easier bolt alignment.
Also known as: floating nut, captive nut plate |
| Flush‑head screw |
A screw designed to sit level with or below the surface when installed, typically using a countersunk head.
Also known as: flush screw |
| Fluted dowel pin |
A dowel pin with longitudinal flutes that allow compression and improved interference fit.
Also known as: fluted pin |
| Form A washer |
A standard flat washer with a plain edge, used for general load distribution.
Also known as: plain washer Form A Learn more → |
| Form B washer |
A flat washer with a chamfered edge for neater appearance and reduced interference.
Also known as: plain washer Form B Learn more → |
| Framework construction |
Building or assembling structural frameworks using threaded rod and associated components.
Also known as: framework assembly |
| Friction coefficient (fasteners) |
The measure of friction between fastener threads and bearing surfaces, strongly influencing torque–tension behaviour.
Also known as: thread friction coefficient Learn more → |
| Friction‑reducing coating |
A surface treatment designed to lower friction during tightening, improving preload consistency.
Also known as: low‑friction coating Learn more → |
| Full nut |
A standard-height nut providing maximum thread engagement for strong, load-bearing joints.
Also known as: standard nut Learn more → |
| Fully threaded rod |
A rod threaded along its entire length for general fastening, bracing and studding applications.
Also known as: allthread, threaded rod Learn more → |
| Galvanic corrosion |
Corrosion caused when dissimilar metals are in electrical contact in the presence of an electrolyte.
Also known as: bimetallic corrosion Learn more → |
| Galvanised thread allowance |
A tolerance adjustment applied to threads to accommodate coating thickness from hot‑dip galvanizing.
Also known as: HDG thread allowance Learn more → |
| Gauge length (threaded rod) |
The measured length between reference points on a threaded rod used for accurate cutting or installation.
Also known as: measured length |
| General engineering (machine screws) |
Engineering applications requiring precise, repeatable fixings using machine screws.
Also known as: engineering applications Learn more → |
| Geometric progression (BA pitch) |
The mathematical rule where BA thread pitch decreases by a factor of 0.9 for each size increment.
Also known as: BA pitch progression Learn more → |
| Gib‑head key |
A taper key with an enlarged head (gib) used for easier installation and removal.
Also known as: gib key |
| Global metric adoption |
The widespread international shift to ISO metric threads across Europe, Asia and most of the world.
Also known as: international metric adoption Learn more → |
| Grade 10.9 steel |
A high‑strength alloy steel used for bolts and fasteners requiring superior tensile and yield performance.
Also known as: 10.9 high tensile Learn more → |
| Grade 12.9 steel |
A very high‑strength alloy steel used for socket head cap screws and critical mechanical joints.
Also known as: 12.9 high tensile Learn more → |
| Grade 8.8 steel |
A high‑tensile carbon steel grade used for threaded rod requiring higher load capacity.
Also known as: 8.8 high tensile Learn more → |
| Grip length (fasteners) |
The total thickness of the materials being clamped by a bolt, excluding washers and nuts.
Also known as: grip range |
| Grip range (blind rivets) |
The material thickness range a blind rivet is designed to clamp securely.
Also known as: rivet grip |
| Grooved pin |
A press‑fit pin with longitudinal grooves that expand radially to create interference‑fit retention.
Also known as: groove pin |
| Grooved snap ring |
A round-wire retaining ring designed to sit in a groove and provide axial retention.
Also known as: round-wire snap ring |
| Half nut |
A thinner nut used where space is limited or as a locking partner in jam-nut arrangements.
Also known as: jam nut |
| Hanger bolt |
A dual‑thread bolt with a wood screw thread on one end and a machine thread on the other, used to join timber to metal.
Also known as: dual‑thread bolt |
| Hardenability |
A steel’s ability to form hardened microstructures during quenching, influenced by alloying elements such as chromium and molybdenum.
Also known as: depth of hardening Learn more → |
| Hardened and tempered |
A two‑stage heat treatment process where steel is first hardened by quenching and then reheated to restore ductility.
Also known as: quenched and tempered Learn more → |
| Hardened parallel pin |
A precision‑ground parallel pin hardened for wear resistance and accurate alignment.
Also known as: hardened dowel pin |
| Hardened tip (driver bits) |
A heat‑treated tip designed to resist wear and deformation during high‑torque driving.
Also known as: hardened bit tip Learn more → |
| Hardened washer |
A washer heat‑treated to resist indentation under high clamping loads.
Also known as: high‑strength washer |
| Hardened‑steel driver bit |
A driver bit manufactured from hardened steel to improve wear resistance, torque strength and service life.
Also known as: heat‑treated driver bit Learn more → |
| Hardness class (set screws) |
A classification defining hardness and torsional strength requirements for set screws.
Also known as: set screw hardness Learn more → |
| Head accessibility |
The ease with which a fastener head can be reached by a tool during installation.
Also known as: tool access Learn more → |
| Head geometry |
The shape and dimensions of a screw head, affecting clearance, bearing area and tool engagement.
Also known as: head shape Learn more → |
| Head profile |
The shape and height of a fastener head, influencing appearance, load distribution and tool engagement.
Also known as: head shape Learn more → |
| Headless screw |
A screw without a head, typically used for adjustment, retention or as a mechanical stop.
Also known as: grub screw, set screw with shank |
| Head‑to‑tip measurement |
The method of measuring fastener length from under the head to the end of the threaded shank.
Also known as: under‑head length |
| Heating installations |
Plumbing or heating systems that may use brass threaded rod for corrosion resistance and non‑sparking properties.
Also known as: heating systems |
| Heat‑treated microstructure |
The internal arrangement of phases in steel after quenching and tempering, determining strength and ductility.
Also known as: tempered microstructure Learn more → |
| Heavy‑duty grooved pin |
A grooved pin with deeper or reinforced grooves for high‑load or industrial applications.
Also known as: heavy grooved pin |
| Heavy‑duty retaining ring |
A thicker, stronger retaining ring designed for high-load or high-vibration shaft or bore retention.
Also known as: heavy circlip |
| Heavy‑series flange bolt |
A hexagon bolt with an enlarged flange providing increased bearing area and improved load distribution.
Also known as: heavy flange bolt |
| Heavy‑series nut |
A nut with increased height and strength for structural or high‑load applications.
Also known as: heavy‑pattern nut |
| Heavy‑type spring lock washer |
A split spring washer with increased thickness for higher tension and improved resistance to loosening.
Also known as: heavy split washer |
| Helical insert |
A coiled wire insert used to repair or reinforce internal threads in softer materials.
Also known as: thread insert, Helicoil |
| Helical spring washer |
A split‑ring washer providing spring tension to resist loosening under vibration.
Also known as: split lock washer |
| Heritage engineering |
The maintenance, restoration and operation of legacy machinery, vehicles and equipment built before metrication.
Also known as: restoration engineering Learn more → |
| Heritage machinery |
Older machinery built using imperial thread forms that must be matched during restoration.
Also known as: vintage machinery Learn more → |
| Heritage Whitworth engineering |
The continued use of Whitworth threads in classic vehicles, steam engines, heritage railways and pre‑metric industrial equipment.
Also known as: Whitworth heritage use Learn more → |
| Hex key |
A hand tool used to drive internal‑hexagon screws.
Also known as: Allen key |
| Hex nut strength matching |
The requirement that a nut must match or exceed the strength grade of the bolt it is paired with.
Also known as: nut–bolt strength matching |
| Hex socket key |
A tool designed to drive socket head screws with internal hex recesses.
Also known as: socket hex key |
| Hexagon bolt |
A bolt with a six‑sided head, typically used with a spanner or socket.
Also known as: hex bolt, hex head bolt Learn more → |
| Hexagon head pipe plug |
A pipe plug with an external hex head used to seal threaded ports.
Also known as: hex head plug |
| Hexagon nut |
A six-sided nut used with bolts, screws and threaded rod for general fastening applications.
Also known as: hex nut Learn more → |
| Hexagon set screw |
A fully threaded hexagon‑headed fastener used for clamping and assembly.
Also known as: hex set screw Learn more → |
| Hexagon socket cap screw |
A high‑strength screw with a cylindrical head and internal hex drive for compact, high‑torque fastening.
Also known as: socket cap screw Learn more → |
| Hexagon socket pipe plug |
A pipe plug with an internal hex drive for sealing threaded connections.
Also known as: internal‑hex plug |
| Hexalobular drive |
A six‑lobe internal drive system providing high torque transfer and reduced cam‑out.
Also known as: Torx drive |
| High nut |
A taller nut providing increased thread engagement and higher load capacity.
Also known as: tall nut |
| High preload applications |
Applications requiring high clamping force, often using fine‑pitch threads such as UNF.
Also known as: high clamping force applications |
| High‑duty collated‑tool operation |
The demanding screw‑driving conditions typical of Makita 6833‑series tools, requiring hardened‑steel bits for durability.
Also known as: heavy‑duty auto‑feed operation Learn more → |
| High‑reach driver bit |
A long driver bit designed for auto‑feed tools that require extended reach, such as the 174 mm Senco DS‑series format.
Also known as: extended‑length driver bit Learn more → |
| High‑strength nut |
A nut manufactured to withstand high tensile loads, typically used with high‑strength bolts.
Also known as: strength‑graded nut Learn more → |
| High‑strength self‑drilling screw |
A self‑drilling screw designed for structural metal‑to‑metal connections requiring high tensile and shear capacity.
Also known as: structural self‑driller |
| High‑strength structural bolt |
A bolt designed for preloaded or high‑duty structural steel joints, offering high tensile and shear capacity.
Also known as: HV bolt, structural bolt Learn more → |
| High‑stress assembly (threaded) |
A mechanical joint subjected to significant tensile, shear or vibrational loads, often requiring fine‑pitch threads.
Also known as: high‑load threaded assembly |
| High‑temperature fastener |
A fastener designed to maintain strength and stability at elevated temperatures.
Also known as: heat‑resistant fastener |
| High‑tensile fine thread |
A fine‑pitch thread providing increased tensile strength due to greater engagement per unit length.
Also known as: high‑strength fine thread |
| High‑tensile steel |
Steel with increased strength used for demanding applications such as Grade 8.8 threaded rod.
Also known as: high tensile Learn more → |
| High‑torque internal drive |
A recess designed to transmit high tightening torque using an internal tool, such as a hex socket.
Also known as: internal hex drive |
| High‑volume bit usage |
The intensive screw‑driving conditions found in drywall, timber framing and site work, requiring durable hardened‑steel bits.
Also known as: heavy‑duty bit usage Learn more → |
| High‑volume thread manufacturing |
Production of threaded fasteners optimised for speed and consistency, enabled by the simplified geometry of Unified threads.
Also known as: mass‑production threadmaking |
| Hilti SMD57 compatibility |
The requirement for driver bits to match the exact length, diameter and PH2 geometry needed for the Hilti SMD 57 auto‑feed screwdriver.
Also known as: SMD57‑compatible bits Learn more → |
| Historical thread systems |
The imperial and metric thread traditions that developed separately and continue to coexist in modern engineering.
Also known as: thread system heritage Learn more → |
| Hole depth requirement (mechanical ties) |
The minimum drilled depth required for a mechanical wall tie to seat correctly and allow full sleeve expansion.
Also known as: drill depth requirement Learn more → |
| Hollow sealing washer |
A hollow copper washer designed to deform and create a fluid‑tight seal in threaded joints.
Also known as: hollow copper washer |
| Hot dip galvanising (HDG) |
A thick zinc coating applied by immersing fasteners in molten zinc, providing excellent long-term corrosion resistance.
Also known as: HDG, galvanised coating Learn more → |
| HV nut |
A high‑strength nut used in preloaded structural bolting assemblies.
Also known as: structural preload nut Learn more → |
| HVAC |
Heating, ventilation and air conditioning systems that often use threaded rod for suspending ductwork and equipment.
Also known as: building services |
| Hydrogen bake‑out |
A post-plating heat treatment used to drive out absorbed hydrogen and reduce embrittlement risk.
Also known as: de-embrittlement bake Learn more → |
| Hydrogen embrittlement |
A failure mode where hydrogen atoms diffuse into high-strength steel, causing delayed brittle fracture under load.
Also known as: hydrogen-induced cracking Learn more → |
| Hydrogen embrittlement (fasteners) |
A failure mechanism where absorbed hydrogen reduces ductility and causes cracking under load.
Also known as: HE cracking Learn more → |
| Hydrogen risk in zinc plating |
The potential for hydrogen absorption during electroplating, which can cause embrittlement in high-strength fasteners.
Also known as: hydrogen embrittlement risk Learn more → |
| Hygiene‑critical material |
A material suitable for environments requiring high cleanliness, corrosion resistance and non‑contamination.
Also known as: sanitary-grade material |
| Impact‑tool compatibility |
The suitability of a drive type for use with impact drivers or powered tools.
Also known as: impact‑rated drive |
| Imperial thread designation |
The naming format used for imperial fasteners, typically combining diameter, TPI and thread system.
Also known as: Unified thread designation Learn more → |
| Imperial thread system |
A family of inch‑based thread forms including Whitworth, UNC, UNF, BSF and BA, developed before global metrication.
Also known as: inch‑based thread system Learn more → |
| Improved tightening |
The enhancement of torque control and preload accuracy achieved by using a washer to reduce friction and surface irregularities.
Also known as: tightening consistency |
| Insertion depth (threaded inserts) |
The required depth for installing a threaded insert to ensure full engagement and load capacity.
Also known as: insert seating depth |
| Insertion torque (threaded inserts) |
The torque required to install a threaded insert into its parent material.
Also known as: insert installation torque |
| Inspection certificate |
A document providing verification of material, testing and conformity for metallic products and fasteners.
Also known as: EN 10204 certificate |
| Instrumentation applications |
Precision applications using miniature thread forms such as BA.
Also known as: instrument work Learn more → |
| Interchangeability (threads) |
The ability for threaded components from different manufacturers to fit and function together reliably.
Also known as: thread compatibility Learn more → |
| Interchangeability breakthrough (Whitworth) |
The engineering revolution created by Whitworth’s unified thread form, enabling components from different workshops to fit together.
Also known as: Whitworth interchangeability Learn more → |
| Interchangeability limitation (BSF vs BSW) |
The fact that BSF and BSW share geometry but cannot be interchanged due to different pitches.
Also known as: BSF/BSW non‑interchangeability Learn more → |
| Interchangeable fine‑thread system (Unified) |
A harmonised fine‑pitch thread family enabling compatibility across UK, US and Canadian manufacturing.
Also known as: Unified fine‑thread interchangeability Learn more → |
| Interchangeable Unified thread system |
A harmonised thread family designed so that components produced in different countries fit and function together.
Also known as: Unified interchangeability Learn more → |
| Internal retaining ring |
A retaining ring fitted into a groove inside a bore to prevent axial movement of components.
Also known as: internal circlip |
| Internal thread tolerance class |
A designation defining the tolerance and deviation of internal threads, such as 6H or 4H.
Also known as: nut thread class |
| Internal‑drive pipe plug |
A pipe plug with an internal drive feature such as a hex socket for sealing threaded ports.
Also known as: internal‑hex pipe plug |
| Internal‑thread parallel pin |
A parallel pin with an internal thread for extraction or secure axial positioning.
Also known as: threaded extraction pin |
| Internal‑thread taper pin |
A taper pin with an internal thread for axial extraction and precise positioning.
Also known as: threaded taper pin |
| Internal‑tooth lock washer |
A lock washer with serrations on the inner edge that grip the fastener head or nut to resist loosening.
Also known as: internal serrated washer |
| International thread unification (metric) |
The post‑WWII effort led by ISO to merge European metric thread systems into a single global standard.
Also known as: ISO metric unification Learn more → |
| ISO |
The International Organization for Standardization, responsible for developing globally recognised engineering and manufacturing standards.
Also known as: International Organization for Standardization |
| ISO fit class |
A designation defining the combined tolerance relationship between internal and external ISO metric threads.
Also known as: metric fit class |
| ISO metric coarse thread |
The standard metric thread series with larger pitch values, used for general‑purpose fasteners.
Also known as: metric coarse thread Learn more → |
| ISO metric fine thread |
A metric thread series with reduced pitch for improved preload control and vibration resistance.
Also known as: metric fine thread (ISO) Learn more → |
| ISO Metric Screw Thread |
The globally unified metric thread system defined by ISO, using a 60° V‑profile with flat crests and roots.
Also known as: ISO metric thread Learn more → |
| Jam nut |
A thin nut used to lock a second nut in place and prevent loosening.
Also known as: lock nut, half nut |
| Jigs and fixtures |
Precision tools and supports used in manufacturing, often assembled using socket head cap screws.
Also known as: manufacturing jigs |
| Joinery work (bolts) |
Timber assembly tasks where cup square bolts are used for secure, rotation‑resistant fastening.
Also known as: timber joinery |
| Joining |
Using threaded rod to connect or secure components together.
Also known as: joining components |
| Joining (imperial) |
Using imperial threaded rod to connect or secure components.
Also known as: joining components |
| Joining components (imperial) |
Connecting parts using imperial threaded rod, nuts and washers.
Also known as: joining assemblies |
| Joint preload |
The clamping force generated in a bolted joint when the fastener is tightened.
Also known as: bolt preload, clamp load |
| Joint relaxation |
The loss of preload in a bolted joint over time due to embedding, material creep or surface settling.
Also known as: preload loss, bolt relaxation |
| Keensert |
A solid threaded insert with locking keys used to reinforce or repair internal threads in softer materials.
Also known as: key‑locking insert, solid threaded insert |
| Keyseat |
The machined recess in a shaft or hub that forms one side of a keyway for torque transmission.
Also known as: shaft keyseat |
| Keyway |
A machined slot in a shaft or hub designed to accept a key for torque transmission.
Also known as: key slot |
| Knurled handle |
A handle with a textured knurled surface for improved grip during manual adjustment.
Also known as: knurled operating handle |
| Knurled thumb nut |
A nut with a knurled outer surface for tool‑free tightening by hand.
Also known as: thumb nut |
| Knurled thumb screw |
A screw with a knurled head for hand tightening without tools.
Also known as: thumb screw |
| K‑factor (nut factor) |
A coefficient used in torque calculations to estimate the relationship between applied torque and resulting preload.
Also known as: nut factor, torque coefficient |
| Landscaping structures |
Outdoor timber or mixed‑material structures assembled using cup square bolts.
Also known as: garden structures |
| Leaf‑to‑leaf connection |
The structural link formed between the inner and outer masonry leaves of a cavity wall using mechanical ties.
Also known as: masonry leaf connection Learn more → |
| Left‑hand thread nut |
A nut with a left‑hand thread used where rotation direction would loosen a standard right‑hand nut.
Also known as: LH nut |
| Legacy machinery |
Older equipment built using imperial thread forms that must be matched during maintenance or restoration.
Also known as: heritage machinery Learn more → |
| Legacy plant |
Industrial machinery and equipment built using imperial fasteners that must be matched during maintenance or repair.
Also known as: legacy equipment Learn more → |
| Length selection (cavity ties) |
Choosing the correct tie length to span the cavity while ensuring adequate embedment into both masonry leaves.
Also known as: cavity tie length choice Learn more → |
| Length selection (starter ties) |
The process of choosing the correct TIGER tie length for tying new masonry to existing substrates.
Also known as: starter tie length choice Learn more → |
| Lifting eye bolt |
A bolt with an integrated lifting eye used for load handling and attachment points.
Also known as: eye bolt |
| Lifting eye nut |
A nut with an integrated lifting eye used for load attachment.
Also known as: eye nut |
| Lighting hardware |
Electrical fittings and components where brass machine screws are commonly used for appearance and conductivity.
Also known as: lighting fittings |
| Light‑duty coiled spring pin |
A coiled spring pin designed for low insertion force and reduced radial stress.
Also known as: light coiled pin |
| Load distribution (nut) |
The spreading of clamping force across the bearing surface when a nut is tightened.
Also known as: load spread |
| Load distribution (Whitworth radiused form) |
The even spread of stress across the thread flanks due to Whitworth’s rounded crests and roots.
Also known as: Whitworth load distribution Learn more → |
| Load path (bolted joint) |
The route through which forces travel in a bolted assembly, affecting stiffness and preload retention.
Also known as: joint load path |
| Load spreading |
The distribution of bolt clamping force over a wider area using washers.
Also known as: load distribution |
| Load‑spreading head |
A head style with a wide bearing surface that distributes clamping force over a larger area.
Also known as: wide bearing head |
| Load‑spreading washer |
A washer designed to distribute clamping force over a larger area, reducing the risk of material deformation.
Also known as: load-distribution washer |
| Lock nut |
A nut designed to resist loosening under vibration or movement.
Also known as: locking nut |
| Lock nut with non‑metallic insert |
A nut incorporating a polymer insert to provide prevailing‑torque resistance.
Also known as: nylon insert nut, nyloc nut |
| Lock washer |
A washer designed to resist loosening of a fastener through friction, tension or mechanical interference.
Also known as: locking washer |
| Locking mechanism (nut) |
A feature that prevents a nut from loosening under vibration or movement, such as nylon inserts or deformed threads.
Also known as: nut locking feature |
| Locking plate |
A plate with one or more tabs used to secure multiple fasteners against rotation.
Also known as: tab plate, locking tab plate |
| Locking tab washer |
A washer with one or more tabs that are bent against a nut or bolt head to prevent rotation.
Also known as: tab washer |
| Long sleeve nut |
An extended‑length nut providing increased internal thread engagement for tensioning or clamping.
Also known as: extended sleeve nut |
| Long-term performance |
The ability of a bolted joint to maintain strength, alignment and corrosion resistance over time.
Also known as: durability |
| Long‑engagement stud |
A double‑end stud with extended thread length on both ends to provide deeper engagement in tapped holes.
Also known as: long‑thread stud |
| Long‑service‑life bit |
A hardened‑steel driver bit engineered to withstand high‑volume screw‑driving without premature wear.
Also known as: durable driver bit Learn more → |
| Low‑profile thumb screw |
A thumb screw with reduced head height for applications requiring compact manual fastening.
Also known as: low‑type thumb screw |
| Machine screw |
A precision fastener designed for use with tapped holes, threaded inserts or paired nuts.
Also known as: machine bolt Learn more → |
| Machine tooling |
Tools and fixtures used in machining operations, often assembled using high‑strength socket cap screws.
Also known as: tooling assemblies Learn more → |
| Machined assemblies (imperial) |
Precision components requiring fine‑pitch imperial threads such as BSF or UNF.
Also known as: machined components |
| Machinery assembly (bolts) |
Using bolts to assemble, align or secure machinery components.
Also known as: machine assembly Learn more → |
| Machinery installation |
The process of installing machinery using threaded rod for alignment, support or anchoring.
Also known as: machine installation |
| Magnetic behaviour |
Whether a fastener is attracted to magnets, determined by its microstructure and alloy composition.
Also known as: magnetism |
| Maintenance (imperial fasteners) |
Repair or upkeep of equipment requiring imperial threaded rod and matching components.
Also known as: imperial maintenance Learn more → |
| Makita 6830 / 6831 compatibility |
The requirement for driver bits to match the exact 110 mm length and 6 mm diameter used by Makita 6830 and 6831 auto‑feed screwdrivers.
Also known as: 6830/6831‑compatible bits Learn more → |
| Makita 6833 / 6836 / 6835DWD compatibility |
The requirement for driver bits to match the exact 127 mm length and 5 mm diameter used by Makita 6833, 6836 and 6835DWD auto‑feed screwdrivers.
Also known as: 6833‑series compatible bits Learn more → |
| Mandrel material (blind rivet) |
The material of the pull mandrel used to expand the rivet body during installation.
Also known as: rivet mandrel material |
| Manual‑installation drive |
A drive type best suited to hand tools rather than powered drivers.
Also known as: hand‑tool drive |
| Marine fittings | Components used in marine environments where corrosion resistance is critical. Learn more → |
| Marine‑grade stainless steel |
A stainless steel alloy with enhanced resistance to chlorides and corrosion, typically containing molybdenum.
Also known as: A4 stainless, 316 stainless Learn more → |
| Martensitic stainless steel |
A hardenable stainless steel used for high‑strength fasteners requiring wear resistance.
Also known as: A5 stainless (in some classifications) Learn more → |
| Martensitic transformation |
A rapid, diffusionless phase change that occurs during quenching, producing a very hard but brittle structure.
Also known as: martensite formation |
| Masonry‑to‑masonry tie |
A fixing used to connect new masonry to existing brick, block or concrete structures.
Also known as: masonry connection tie Learn more → |
| Mass‑production thread form |
A thread geometry optimised for rapid, economical manufacturing, such as the flat‑topped Unified profile.
Also known as: production‑optimised thread Learn more → |
| Matched thread system |
The requirement that nuts and bolts use the same thread form and pitch to ensure safe engagement.
Also known as: thread matching |
| Mating thread length |
The length of internal thread engagement required to achieve full strength in a bolted joint.
Also known as: thread engagement length |
| Mechanical builds |
Assemblies involving mechanical components secured using bolts such as socket cap screws.
Also known as: mechanical assemblies Learn more → |
| Mechanical locking feature |
A physical feature that prevents fastener loosening, such as serrations, tabs or deformed threads.
Also known as: mechanical lock |
| Mechanical property class |
A numerical designation defining the tensile strength and yield ratio of carbon and alloy steel fasteners.
Also known as: property class Learn more → |
| Mechanical wall tie |
A wall tie that relies on mechanical expansion rather than resin or plugs to secure itself within masonry.
Also known as: expanding wall tie Learn more → |
| Metric coarse thread |
The default ISO metric thread pitch for a given diameter, used unless a fine pitch is specified.
Also known as: coarse pitch metric Learn more → |
| Metric designation |
The standard way of specifying metric fasteners using the M prefix followed by nominal diameter and length.
Also known as: ISO metric designation Learn more → |
| Metric stud bolt |
A stud bolt manufactured to metric thread standards with controlled dimensional tolerances.
Also known as: metric stud |
| Metric thread |
A thread form defined by ISO standards, used on metric threaded rod.
Also known as: ISO metric thread Learn more → |
| Metric thread pitch series |
The standardised set of coarse and fine pitches for ISO metric threads.
Also known as: ISO pitch series Learn more → |
| Metric thread profile |
The 60° symmetrical V‑thread form used for ISO metric screw threads.
Also known as: ISO metric profile Learn more → |
| Metric thread series (coarse, fine, extra‑fine) |
The three ISO metric pitch families: coarse (M), fine (MF) and extra‑fine, each optimised for different engineering applications.
Also known as: metric pitch series Learn more → |
| Metrication |
The transition from imperial to metric measurement systems in engineering and manufacturing.
Also known as: metric transition Learn more → |
| Metrication (UK engineering) |
The gradual transition in the UK from imperial thread systems to ISO metric threads from the 1960s to 1990s.
Also known as: UK metric transition Learn more → |
| Metric‑derived imperial thread |
A thread system used in imperial‑dominant industries but based entirely on metric pitch and diameter relationships, such as BA.
Also known as: metric‑based imperial thread Learn more → |
| Metric–imperial coexistence |
The continued use of both metric and imperial fastener systems due to legacy equipment, regional standards and historical development.
Also known as: dual thread-system usage Learn more → |
| Metrification (non‑standard term) |
A non‑standard variant sometimes used informally instead of the correct term “metrication”.
Also known as: incorrect metrication term Learn more → |
| Micro‑movement (joint slip) |
Small relative movement between clamped components that can reduce preload or cause fretting.
Also known as: joint micro‑slip |
| Mild steel |
A low‑carbon steel used for general‑purpose threaded rod applications.
Also known as: low carbon steel Learn more → |
| Miniature engineering (BA context) |
The field of small‑scale mechanical construction where BA threads were historically dominant.
Also known as: model engineering, miniature mechanisms Learn more → |
| Miniature thread |
A small‑diameter thread used in precision instruments, electrical components and fine mechanisms.
Also known as: instrument thread |
| Minimum thread engagement |
The minimum length of thread engagement needed to prevent stripping under load.
Also known as: minimum engagement |
| Model engineering |
Small‑scale engineering work often using BA thread forms for miniature assemblies.
Also known as: miniature engineering Learn more → |
| Moisture‑break feature |
A design element on a cavity tie that prevents water from travelling across the cavity from one leaf to the other.
Also known as: moisture barrier feature Learn more → |
| Motorsport fine‑thread application |
Use of fine‑pitch threads in high‑performance automotive and motorsport assemblies requiring precise torque control.
Also known as: motorsport fine thread use |
| MPa (megapascal) |
A unit of stress equal to one newton per square millimetre, used to express tensile and yield strength.
Also known as: megapascal Learn more → |
| Mudguard washer |
A large‑diameter washer used to spread load over thin sheet materials.
Also known as: repair washer, penny washer |
| Multi‑model Senco compatibility |
The ability of a driver bit to fit multiple Senco DS‑series tools, including DS212, DS215, DS232, DS235, DS5525 and DS5550.
Also known as: Senco multi‑tool compatibility Learn more → |
| Multi‑start thread |
A thread with two or more parallel thread starts, providing faster linear travel per rotation.
Also known as: multiple‑start thread |
| Mushroom head profile |
A low, domed screw head providing a broad seating area and smooth visible finish.
Also known as: mushroom head Learn more → |
| Mushroom‑head screw |
A screw with a wide, low‑profile mushroom‑shaped head offering good bearing area and a neat appearance.
Also known as: mushroom head, mushroom screw Learn more → |
| Mushroom‑head square‑neck bolt |
A timber bolt with a mushroom‑shaped head and square neck that prevents rotation during tightening.
Also known as: mushroom bolt |
| National Coarse (NC) thread |
A pre‑Unified American coarse thread series that was replaced by UNC after 1948.
Also known as: NC thread Learn more → |
| National Fine (NF) thread |
A pre‑Unified American fine‑pitch thread series replaced by UNF after 1948.
Also known as: NF thread Learn more → |
| National metric standards (pre‑ISO) |
The individual metric thread systems adopted by France, Switzerland and Germany before ISO unification.
Also known as: pre‑ISO national metric threads Learn more → |
| New‑wall stabilisation |
The structural stabilisation achieved by tying a new wall into an existing substrate using starter ties.
Also known as: new wall restraint Learn more → |
| Nominal diameter |
The designated diameter of a fastener thread, used for sizing and specification rather than exact measurement.
Also known as: thread diameter Learn more → |
| Non‑electrolytic coating |
A coating applied without electrical current, eliminating hydrogen introduction into steel.
Also known as: non-electroplated coating Learn more → |
| Non‑magnetic material | A material that does not attract magnets, such as brass, used in electrical and instrumentation applications. Learn more → |
| Non‑pressure‑tight thread |
A parallel pipe thread intended for mechanical assembly rather than fluid sealing.
Also known as: parallel pipe thread |
| Non‑sparking material |
A material that does not produce sparks when struck, making it suitable for explosive or flammable environments.
Also known as: spark‑resistant material |
| Non‑standardised pre‑Whitworth threads |
The diverse, incompatible thread forms used by workshops before Whitworth introduced a unified standard.
Also known as: pre‑Whitworth workshop threads Learn more → |
| Numbered thread series (BA) |
A thread sizing system where sizes are designated by numbers (0BA to 16BA) rather than diameters.
Also known as: BA numbering system Learn more → |
| Nut factor (K‑factor) |
A coefficient used to estimate the relationship between applied torque and resulting preload in a bolted joint.
Also known as: K‑factor, torque coefficient |
| Nut locking feature |
A design feature that prevents a nut from loosening under vibration or movement.
Also known as: nut locking mechanism |
| Nut thread engagement |
The amount of bolt thread that is fully engaged with the nut, affecting strength and load capacity.
Also known as: thread engagement depth |
| Nuts |
Threaded fasteners used with threaded rod to clamp or secure components.
Also known as: hex nuts Learn more → |
| Nylon insert nut |
A locking nut with a nylon ring that grips the bolt threads to resist loosening.
Also known as: nyloc nut |
| OEM‑grade cut‑tip |
A precision‑machined bit tip designed to match original equipment manufacturer specifications for accuracy and fit.
Also known as: precision cut‑tip Learn more → |
| Open‑end blind rivet |
A blind rivet with an open end that allows the mandrel to break off and fall away after installation.
Also known as: standard blind rivet |
| Open‑ended wrench |
A hand tool with U‑shaped jaws used to tighten or loosen hexagon fasteners.
Also known as: open‑end spanner |
| Out‑of‑round thread |
A thread whose circular form is distorted, reducing fit quality and load‑carrying capacity.
Also known as: ovalised thread |
| Oval‑head tapping screw |
A raised countersunk self‑tapping screw with a domed top for a decorative flush finish.
Also known as: raised countersunk tapping screw |
| Overall length |
The full end‑to‑end length of a fastener, used for studs and allthread.
Also known as: total length Learn more → |
| Oversized threads (HDG) |
Thread tolerances increased to accommodate the thick zinc layer produced by hot dip galvanising.
Also known as: HDG oversized nuts Learn more → |
| Over‑torque |
Applying torque beyond the recommended limit, risking thread stripping, bolt yielding or joint failure.
Also known as: excessive torque |
| Pan head profile |
A rounded screw head with a wide seating area, used for general-purpose machine screw applications.
Also known as: pan head Learn more → |
| Pan head screw |
A rounded, slightly domed head used on machine screws, available with slot or Pozi drives.
Also known as: pan head Learn more → |
| Pan‑head tapping screw |
A self‑tapping screw with a slightly domed head and wide bearing surface for general‑purpose fastening.
Also known as: pan tapping screw |
| Parallel key |
A rectangular key used to transmit torque between a shaft and hub without taper action.
Also known as: rectangular key |
| Parallel pin |
A cylindrical pin with constant diameter used for alignment, location and positioning.
Also known as: parallel dowel pin |
| Parallel pipe thread |
A cylindrical pipe thread used for mechanical joints where sealing is not achieved on the thread flanks.
Also known as: BSPP thread |
| Part‑thread bolt |
A bolt with an unthreaded shank section to improve shear performance and alignment in joints.
Also known as: partial‑thread bolt Learn more → |
| Passivation by chromium |
The formation of a protective oxide layer on stainless steel surfaces due to chromium content, providing corrosion resistance.
Also known as: chromium oxide passivation Learn more → |
| Passivation layer |
A thin chemical conversion coating applied after zinc plating to enhance corrosion resistance.
Also known as: chromate layer Learn more → |
| Penny washer |
A large‑diameter washer used to spread load over a wide area.
Also known as: repair washer, mudguard washer |
| Penny washer behaviour |
The way a large‑diameter washer spreads load across thin or soft materials to prevent pull‑through.
Also known as: repair washer behaviour |
| PH2 recess compatibility |
The suitability of a driver bit for use with PH2 (Phillips #2) screw recesses, the most common size for drywall and timber screws.
Also known as: PH2 fit Learn more → |
| PH2 × 110 mm specification |
The combination of PH2 drive size and 110 mm length required for correct operation in Makita 6830 / 6831 auto‑feed systems.
Also known as: 110 mm PH2 bit Learn more → |
| PH2 × 116 mm specification |
The specific combination of PH2 drive size and 116 mm length required for correct operation in the Hilti SMD 57 auto‑feed system.
Also known as: 116 mm PH2 bit Learn more → |
| PH2 × 127 mm specification |
The combination of PH2 drive size and 127 mm length required for correct operation in Makita 6833, 6836 and 6835DWD auto‑feed systems.
Also known as: 127 mm PH2 bit Learn more → |
| PH2 × 174 mm specification |
The combination of PH2 drive size and 174 mm length required for correct operation in Senco DS‑series auto‑feed systems.
Also known as: 174 mm PH2 bit Learn more → |
| Phosphate coating |
A conversion coating applied to steel to improve corrosion resistance and provide a base for lubrication or painting.
Also known as: phosphating Learn more → |
| Pipe plug |
A threaded plug used to seal or close off a pipe or port.
Also known as: threaded plug |
| Pipework (imperial installations) |
Plumbing or mechanical pipe systems suspended using imperial threaded rod.
Also known as: pipe suspension Learn more → |
| Pipework suspension |
Using threaded rod to support or hang pipework in building services.
Also known as: pipe suspension Learn more → |
| Pitch diameter |
The theoretical diameter at which the thread thickness equals the space between threads.
Also known as: effective diameter Learn more → |
| Pitch expression |
The method used to describe thread pitch, either in millimetres (metric) or threads per inch (imperial).
Also known as: thread pitch expression |
| Pitch in millimetres |
The metric method of defining thread pitch as the distance between adjacent crests, measured in millimetres.
Also known as: metric pitch measurement Learn more → |
| Pitch progression factor |
The constant 0.9 multiplier used to derive each successive BA pitch size.
Also known as: BA pitch factor |
| Pitch series (imperial) |
The classification of imperial threads by pitch, such as coarse (UNC) and fine (UNF).
Also known as: imperial pitch series Learn more → |
| Plain washer |
A flat washer used to distribute load, protect surfaces and provide a smooth bearing face.
Also known as: flat washer Learn more → |
| Plating thickness |
The thickness of a metallic coating applied to a fastener, affecting corrosion resistance and thread fit.
Also known as: coating thickness Learn more → |
| Point type (set screw) |
The geometry of the tip of a set screw, determining how it engages the mating surface.
Also known as: set screw point form |
| Post‑war thread unification |
The coordinated effort after WWII to standardise British and American thread systems into the Unified Thread Standard.
Also known as: post‑war standardisation Learn more → |
| Pozi drive |
A cross‑shaped screw drive designed to reduce cam‑out and improve torque transfer.
Also known as: Pozidriv Learn more → |
| Pozi drive geometry |
A cross‑shaped recess with additional ribs that improve torque transfer and reduce cam‑out.
Also known as: Pozidriv Learn more → |
| Precision assemblies |
Fine‑tolerance mechanical assemblies often using UNF, BSF or BA threads.
Also known as: precision engineering assemblies Learn more → |
| Precision engineering thread |
A thread used in machinery requiring accurate adjustment, reduced backlash and improved vibration resistance.
Also known as: precision thread Learn more → |
| Precision equipment (imperial) |
Scientific or technical equipment that uses fine‑pitch imperial threads such as BSF or BA for accurate assembly.
Also known as: precision instruments Learn more → |
| Precision instrument thread |
A miniature thread used in scientific instruments, electrical devices and fine mechanisms.
Also known as: instrument thread Learn more → |
| Precision mechanical assemblies |
Fine‑tolerance mechanical components assembled using brass or stainless machine screws.
Also known as: precision assemblies Learn more → |
| Precision‑adjustment thread |
A fine‑pitch thread used where small rotational movement must produce controlled axial displacement.
Also known as: precision thread Learn more → |
| Precision‑fit bolt |
A bolt manufactured with tight dimensional tolerances for accurate alignment in machinery and structural assemblies.
Also known as: close‑fit bolt, precision bolt Learn more → |
| Preload retention |
The ability of a washer to maintain bolt tension under vibration or thermal cycling.
Also known as: tension retention |
| Pressure‑tight pipe thread (historical) |
Early tapered pipe threads used in imperial systems to create sealing joints in steam, gas and hydraulic applications.
Also known as: imperial tapered pipe thread |
| Pressure‑tight thread |
A tapered pipe thread designed to form a pressure‑tight seal on the thread flanks.
Also known as: tapered pipe thread |
| Prevailing torque nut |
A nut that maintains frictional resistance during tightening and loosening to prevent rotation.
Also known as: all-metal lock nut |
| Primary cavity stabilisation |
The structural stabilisation provided by cavity wall ties, preventing the two masonry leaves from moving independently.
Also known as: cavity wall stabilisation Learn more → |
| Professional appearance (bolts) |
A clean, uniform finish achieved using bright zinc plated bolts.
Also known as: clean finish |
| Progressive‑groove pin |
A grooved pin with grooves that vary along the length to provide controlled insertion and retention.
Also known as: progressive grooved pin |
| Projection weld nut |
A weld nut with small projections that localise heat and ensure strong weld attachment to sheet metal.
Also known as: projection nut |
| Proliferation of specialised threads |
The period from 1850–1930 when numerous imperial thread forms emerged for specific industries such as electrical, pipework and fine instruments.
Also known as: specialised thread era Learn more → |
| Proof load |
The maximum load a nut or bolt can sustain without permanent deformation.
Also known as: proof stress Learn more → |
| Proof stress |
The stress at which a fastener begins to deform permanently, used for bolts in ISO 898‑1.
Also known as: yield‑equivalent stress Learn more → |
| Property class marking |
A numerical marking indicating the mechanical strength of a fastener, such as 8.8, 10.9 or 12.9.
Also known as: strength class marking Learn more → |
| Protruding‑head blind rivet |
A blind rivet with a domed head that provides a wide bearing surface for general fastening.
Also known as: domed blind rivet |
| Pull‑through resistance |
The ability of a fastener head to resist being pulled through thin sheet material under load.
Also known as: pull‑through strength |
| Push‑in sealing cap |
A cap inserted by hand to close or protect an opening in mechanical assemblies.
Also known as: push‑fit cap |
| Quality assurance system |
A structured set of processes ensuring consistent fastener quality, traceability and conformity.
Also known as: QA system |
| Quality management system – Automotive |
A quality system meeting automotive industry requirements for process control, traceability and defect prevention.
Also known as: IATF 16949 system |
| Quench severity |
A measure of how rapidly a quenching medium extracts heat from steel, affecting hardness and distortion.
Also known as: quench intensity Learn more → |
| Quenching |
The rapid cooling of heated steel to form a hard martensitic structure.
Also known as: rapid cooling |
| Quench‑and‑temper steel |
Steel that has been hardened by quenching and then reheated to restore ductility while retaining high strength.
Also known as: Q&T steel Learn more → |
| Radial expansion grip |
The outward expansion of a fixing sleeve that creates 360° contact with the substrate for secure anchorage.
Also known as: 360-degree expansion grip |
| Radiused thread profile |
A thread form with rounded crests and roots, characteristic of Whitworth‑based systems including BSF.
Also known as: rounded Whitworth profile |
| Raised countersunk head |
A countersunk screw head with a slightly domed top for improved appearance and bearing area.
Also known as: raised CSK Learn more → |
| Raised countersunk screw |
A screw with a countersunk underside and a slightly domed top for a decorative flush finish.
Also known as: oval‑head screw Learn more → |
| Raised countersunk tapping screw |
A self‑tapping screw with a countersunk underside and a slightly domed top for a decorative flush finish.
Also known as: oval‑head tapping screw |
| Recessed spaces (bolt installation) |
Confined areas where socket head cap screws are used due to their internal hex drive.
Also known as: restricted spaces |
| Reduced stripping risk (fine threads) |
The improved resistance to thread stripping in thin‑walled or hard materials due to increased engagement depth.
Also known as: fine‑thread stripping resistance |
| Reduced‑shank stud |
A double‑end stud with a smaller‑diameter unthreaded shank for alignment or controlled flexibility.
Also known as: waisted stud |
| Relief groove (bolt shank) |
A narrow groove between the head and shank of a bolt to reduce stress concentration.
Also known as: under‑head relief groove |
| Repeatable fixing |
A fastening method that allows components to be removed and reinstalled without damaging the joint.
Also known as: serviceable fixing |
| Restoration work |
Repairing or rebuilding older equipment using original imperial thread forms.
Also known as: restoration engineering Learn more → |
| Restricted‑access installation |
An installation environment where external tools cannot reach the fastener head, requiring internal drives such as hex sockets.
Also known as: limited‑access installation |
| Retaining ring |
A ring installed in a groove on a shaft or in a bore to prevent axial movement of components.
Also known as: circlip, snap ring |
| Retaining washer (push‑on) |
A washer that grips a shaft or stud by friction, holding components in place without threads.
Also known as: push‑on washer, starlock washer |
| Return‑wall connection |
A junction where a new wall returns into an existing wall, requiring mechanical starter ties for structural continuity.
Also known as: return‑wall tie‑in Learn more → |
| Reverse‑taper grooved pin |
A grooved pin with a reverse taper profile providing controlled interference‑fit behaviour.
Also known as: reverse‑taper pin |
| Robotics assemblies |
Mechanical and electromechanical systems assembled using high‑strength socket cap screws.
Also known as: robotics builds |
| Roof bolt |
A bolt with a low‑profile head and cross‑slot drive used for roofing and cladding applications.
Also known as: roofing bolt Learn more → |
| Root radius (Whitworth) |
The rounded root geometry of Whitworth threads, defined as 0.1373 × pitch.
Also known as: Whitworth root rounding Learn more → |
| Root truncation |
The flat removal of material at the root of a thread, used in Unified threads to simplify machining.
Also known as: flat root |
| Rosette washer |
A washer with an enlarged bearing surface for improved load distribution in structural and mechanical assemblies.
Also known as: large‑bearing washer |
| Rotation‑locking feature |
A design element that prevents the fastener from turning during tightening, such as the square neck on carriage bolts.
Also known as: anti‑rotation feature |
| Round head rivet |
A solid rivet with a domed head providing strong bearing area and high shear strength.
Also known as: domed head rivet |
| Rounded crest and root |
A thread geometry where both the crest and root are curved rather than flat or sharp.
Also known as: rounded thread form |
| Rounded crests (Whitworth) |
The rounded top of the Whitworth thread profile designed to improve strength and manufacturability.
Also known as: Whitworth crest form Learn more → |
| Rounded‑root thread |
A thread form with a rounded root to improve fatigue resistance and reduce stress concentration.
Also known as: UNR thread |
| Round‑head square‑neck bolt |
A bolt with a domed head and square neck that locks into timber or metal to prevent rotation.
Also known as: carriage bolt Learn more → |
| Round‑wire snap ring |
A retaining ring made from round wire that expands into a groove to provide axial retention.
Also known as: wire circlip |
| Run‑out (thread) |
The transition zone where the thread profile tapers off at the end of a bolt or screw.
Also known as: thread run‑out |
| Screw plug |
A threaded insert or plug used to close or seal a threaded hole.
Also known as: threaded plug |
| Sealing washer |
A washer designed to create a fluid‑tight or gas‑tight seal under a fastener head or nut.
Also known as: seal washer |
| Seating area |
The surface area of the screw head that contacts the material, affecting load distribution and appearance.
Also known as: bearing area |
| Securing panels |
Using machine screws to attach panels or covers to equipment or enclosures.
Also known as: panel fixing |
| Self colour |
The natural, uncoated appearance of a metal fastener, typically used for stainless steel, brass and unplated steel.
Also known as: natural finish, uncoated steel Learn more → |
| Self-colour nut |
A nut supplied without a plated finish, typically used in indoor or protected environments.
Also known as: black steel nut Learn more → |
| Self‑drilling screw |
A screw with an integrated drill point that drills, taps and fastens in a single operation.
Also known as: drill‑point screw |
| Self‑locking spring washer |
A formed spring washer that provides locking action through elastic deformation and friction.
Also known as: spring lock washer |
| Self‑tapping screw |
A screw that forms or cuts its own mating thread in sheet metal, plastics or timber.
Also known as: tapping screw |
| Sellers 60° thread profile |
The American 60° V‑thread form that influenced the Unified Thread Standard.
Also known as: Sellers thread form Learn more → |
| Semi‑flush finish |
A screw head profile that sits slightly above the surface while remaining low‑profile and unobtrusive.
Also known as: partially flush finish |
| Senco DS‑series driver bit |
A hardened‑steel PH2 driver bit engineered for Senco DS212, DS215, DS232, DS235, DS5525 and DS5550 auto‑feed screwdrivers.
Also known as: Senco DS‑compatible bit Learn more → |
| Serviceable joints |
Joints assembled using machine screws that can be repeatedly opened and closed for maintenance.
Also known as: removable joints |
| Set screw |
A headless or small‑head screw used to secure an object within or against another object, typically via axial pressure.
Also known as: grub screw Learn more → |
| Shaft collar (adjusting ring) |
A ring fitted to a shaft to position or secure components axially.
Also known as: collar ring |
| Shakeproof washer |
A washer with serrations or teeth that bite into the mating surface to resist loosening under vibration.
Also known as: serrated washer |
| Shank length (bolt) |
The unthreaded portion of a bolt used to provide shear strength and alignment.
Also known as: unthreaded length |
| Shear plane (fastener joint) |
The plane along which a bolt or pin may experience shear forces in a joint.
Also known as: shear interface |
| Sheet‑metal tapping screw |
A self‑tapping screw designed specifically for fastening thin sheet metal.
Also known as: sheet‑metal screw |
| Sherardizing |
A thermal diffusion zinc coating process producing a uniform, adherent corrosion‑resistant layer.
Also known as: thermal diffusion galvanizing Learn more → |
| Shim ring |
A precision ring used for axial spacing, alignment and tolerance compensation in mechanical assemblies.
Also known as: shim washer |
| Shoulder screw |
A screw with an unthreaded precision shoulder used as a pivot, guide or bearing surface.
Also known as: shoulder bolt |
| Sir Joseph Whitworth | The engineer who introduced the Whitworth thread form in 1841, the first national screw thread standard. Learn more → |
| Site‑work driver bit |
A hardened‑steel driver bit designed for professional trade environments such as construction sites and timber framing.
Also known as: trade‑grade driver bit |
| Sleeve nut |
A nut with extended length providing increased internal thread engagement for tensioning or clamping.
Also known as: long nut |
| Slotted drive |
A traditional single‑slot recess offering simple tool compatibility but limited torque capacity.
Also known as: slot drive Learn more → |
| Slotted round nut |
A compact round nut with slots for screwdriver or tool engagement, used where radial space is limited.
Also known as: round slotted nut |
| Slotted set screw |
A set screw driven by a slotted recess, used for axial positioning and mechanical locking.
Also known as: slot‑drive set screw Learn more → |
| Slotted spring pin |
A spring pin with a longitudinal slot that compresses during insertion to create radial tension.
Also known as: roll pin, slotted pin |
| Smooth‑finish head |
A head style with a rounded or low‑profile top designed to minimise snagging and improve appearance.
Also known as: rounded head finish Learn more → |
| Snap ring |
A spring-steel ring that snaps into a groove to provide axial retention.
Also known as: circlip |
| Socket head cap screw |
A high‑strength fastener with a cylindrical head and internal hex drive.
Also known as: cap screw, SHCS Learn more → |
| Socket key |
A tool used to drive socket head screws, typically with an internal hex.
Also known as: socket wrench key |
| Solid rivet |
A rivet made from a single piece of metal, installed by deforming the tail to form a permanent joint.
Also known as: solid shank rivet |
| Solid-body threaded insert |
A heavy-duty threaded insert with a solid metal body for creating strong, wear-resistant internal threads.
Also known as: solid insert |
| Specialist applications (imperial) |
Uses of imperial threaded rod in equipment or industries that require traditional thread forms.
Also known as: specialist engineering |
| Specialist equipment (imperial) |
Equipment requiring traditional imperial thread forms for compatibility with older standards or precision assemblies.
Also known as: specialist machinery Learn more → |
| Spherical‑seat washer |
A washer system with spherical and conical mating surfaces used to compensate for angular misalignment.
Also known as: spherical washer set |
| Spiral‑groove pin |
A grooved pin with spiral grooves providing progressive radial expansion and improved retention in vibration‑prone assemblies.
Also known as: spiral grooved pin |
| Split pin |
A two‑pronged pin that is bent after insertion to secure nuts, clevis pins or mechanical linkages.
Also known as: cotter pin |
| Split‑lock washer action |
The spring‑like behaviour of a split washer that applies tension and friction to resist loosening.
Also known as: spring washer action |
| Spray‑applied coating |
A method of applying zinc flake or other coatings using controlled spray deposition.
Also known as: spray coating Learn more → |
| Spring pin |
A hollow, flexible pin that compresses during insertion and expands to create radial tension.
Also known as: tension pin |
| Spring washer |
A washer designed to provide tension and resist loosening under vibration.
Also known as: lock washer |
| Square neck (bolt feature) |
A square section beneath the head of a cup square bolt that prevents rotation during tightening.
Also known as: square shank Learn more → |
| Square nut |
A nut with four sides, offering greater surface contact and resistance to loosening.
Also known as: 4-sided nut |
| Square taper washer |
A washer with a tapered profile used to create a level bearing surface on inclined flanges such as U‑ or I‑sections.
Also known as: taper washer |
| Square underside (roof bolt feature) |
A shaped or square underside beneath the head of a roof bolt that prevents rotation during tightening.
Also known as: anti‑rotation underside |
| Square washer |
A washer with a square outer profile, used in timber construction and channel systems.
Also known as: square plate washer |
| Square‑head bolt |
A bolt with a square head providing large wrenching surfaces and improved grip in fixtures and machine assemblies.
Also known as: square bolt |
| Square‑neck bolt |
A bolt with a square section beneath the head that locks into timber or metal to prevent rotation.
Also known as: anti‑rotation neck Learn more → |
| Stainless steel | A corrosion‑resistant steel alloy used for threaded rod in demanding environments. Learn more → |
| Stainless steel 304 (BS1554) |
A corrosion‑resistant stainless steel grade used for TIGER ties, compliant with BS1554.
Also known as: 304 stainless steel Learn more → |
| Stainless steel alloying |
The combination of chromium, nickel and other elements that give stainless steel its corrosion resistance and mechanical properties.
Also known as: stainless alloy composition Learn more → |
| Stainless steel grade |
A designation defining the alloy composition and corrosion resistance of stainless steel fasteners, such as A2 or A4.
Also known as: A2 grade, A4 grade Learn more → |
| Standardised 60° metric V‑thread |
The universal 60° V‑profile with flat crests and roots used across all ISO metric threads.
Also known as: ISO metric V‑thread Learn more → |
| Standardised thread angle |
A fixed flank angle defined by a thread system, such as Whitworth’s 55° or Unified’s 60°.
Also known as: thread flank angle Learn more → |
| Starter wall tie |
A mechanical fixing used to tie new masonry walls to existing brick, block or concrete substrates.
Also known as: starter tie Learn more → |
| Starter wall tie (mechanical type) |
A mechanical fixing used to tie new masonry walls or extensions to existing structures.
Also known as: mechanical starter tie Learn more → |
| Steelwork (imperial installations) |
Structural steel components where imperial threaded rod may be used for bracing or fixing.
Also known as: steel structures |
| Steelwork connections (bolts) |
Structural joints in steel frameworks assembled using high‑strength bolts.
Also known as: steel connections Learn more → |
| Stock availability line |
A dynamic product‑page indicator showing real‑time pack availability and lead times for bulk bags.
Also known as: stock status message |
| Straightness (threaded rod) |
A manufacturing tolerance defined in DIN 976 that ensures threaded rod remains true along its length.
Also known as: rod straightness Learn more → |
| Strength class |
A numerical designation describing the tensile and yield strength of a fastener material.
Also known as: property class Learn more → |
| Strength‑grade compatibility |
The engineering requirement that nut and bolt strength grades must be compatible to ensure safe load-bearing performance.
Also known as: grade matching Learn more → |
| Strength‑per‑diameter advantage |
The increased tensile strength achieved by using a finer pitch for the same nominal diameter.
Also known as: fine‑thread strength advantage |
| Stress area (thread) |
The effective cross‑sectional area of a threaded fastener used for tensile‑strength calculations.
Also known as: thread stress area |
| Stripping resistance (coarse threads) |
The ability of a coarse‑pitch thread to resist material failure when loaded in softer metals.
Also known as: coarse‑thread stripping strength |
| Structural applications |
Uses of threaded rod in load‑bearing or high‑strength installations.
Also known as: structural work |
| Structural bolt |
A bolt designed for steel construction, offering high tensile strength and controlled geometry for preloaded or non‑preloaded joints.
Also known as: construction bolt Learn more → |
| Structural masonry tie (cavity) |
A fixing used to structurally connect the two leaves of a cavity wall, ensuring load sharing and stability.
Also known as: cavity structural tie Learn more → |
| Structural nut |
A high‑strength nut used in steel construction, designed to meet strict mechanical and dimensional requirements.
Also known as: construction nut Learn more → |
| Structural steelwork |
Steel structures assembled using bolts for load‑bearing connections.
Also known as: steel structures Learn more → |
| Stud bolt |
A threaded fastener without a head, typically used with two nuts or one nut and a tapped hole to clamp components together.
Also known as: stud Learn more → |
| Studwork‑grade driver bit |
A hardened‑steel driver bit designed for timber studwork, drywall framing and other structural timber applications.
Also known as: timber‑framing driver bit Learn more → |
| Substrate anchorage (starter ties) |
The secure mechanical engagement of a starter tie within an existing masonry substrate.
Also known as: starter tie anchorage |
| Surface discontinuity |
A material imperfection such as a seam, lap or inclusion that may affect fastener performance.
Also known as: surface defect |
| Surface‑protection washer |
A washer used to prevent damage to softer materials by distributing load and reducing indentation.
Also known as: protective washer |
| Suspending (imperial) |
Using imperial threaded rod to hang or support equipment or services.
Also known as: suspending services |
| Suspending services |
Using threaded rod to hang or support building services such as pipework, ducting and cable trays.
Also known as: service suspension |
| Symmetrical radiused thread form |
A thread geometry with equal radiusing at crest and root, characteristic of Whitworth threads.
Also known as: Whitworth radiused profile Learn more → |
| Tab washer |
A lock washer with one or more tabs that are bent against a nut, bolt or slot to prevent rotation.
Also known as: locking tab washer |
| Taper key |
A key with a slight taper used to secure a hub to a shaft through wedge action.
Also known as: tapered key |
| Taper pin |
A pin with a slight taper used for precise alignment and secure positioning in mechanical assemblies.
Also known as: tapered pin |
| Taper washer |
A washer with an angled profile used to correct bolt alignment on sloping or angled surfaces.
Also known as: bevel washer |
| Tapered handle |
A handle with a tapered profile used on levers and machine controls.
Also known as: taper handle |
| Tapered pipe thread |
A pipe thread with a taper that forms a pressure‑tight seal through flank interference.
Also known as: BSPT thread |
| Tapered‑head rivet (variant) |
A variant of a countersunk rivet with modified taper geometry for specific sheet‑metal applications.
Also known as: variant countersunk rivet |
| Taper‑action fastening |
A fastening method where a tapered key or component locks into place through wedge action.
Also known as: wedge‑action fastening |
| Tapped hole |
A hole that has been threaded to accept a machine screw.
Also known as: threaded hole |
| Tarnish resistance |
The ability of a material such as brass to resist surface dulling or discolouration over time.
Also known as: anti‑tarnish |
| Tempered martensite |
The microstructure formed when quenched martensite is reheated, providing high strength with improved ductility.
Also known as: tempered structure Learn more → |
| Tempering |
A heat treatment stage where quenched steel is reheated to reduce brittleness and restore toughness.
Also known as: tempering process Learn more → |
| Tensile strength |
The maximum stress a fastener can withstand before breaking, expressed in MPa.
Also known as: ultimate tensile strength Learn more → |
| Tension capacity (wall ties) |
The maximum tensile load a wall tie can resist before failure, measured during standardised testing.
Also known as: tensile capacity |
| Thermal diffusion coating |
A zinc‑based coating applied by diffusion at elevated temperatures, producing a uniform, adherent layer.
Also known as: sherardizing |
| Thermoplastic thread‑forming screw |
A screw designed to form durable internal threads in thermoplastic materials without cracking or overstressing the material.
Also known as: plastic‑forming screw |
| Thread angle |
The included angle between the flanks of a thread, affecting strength and compatibility.
Also known as: included angle Learn more → |
| Thread angle (imperial) |
The angle between the flanks of a thread, such as 55° for Whitworth and 60° for Unified threads.
Also known as: thread flank angle Learn more → |
| Thread damage risk |
The likelihood of thread stripping or galling when incompatible nut and bolt threads are used.
Also known as: thread stripping risk |
| Thread engagement |
The amount of thread contact between a nut and bolt, affecting strength and load capacity.
Also known as: thread contact |
| Thread fit class (Unified) |
A designation describing the tolerance and tightness of Unified threads, such as 1A/1B, 2A/2B and 3A/3B.
Also known as: Unified fit class |
| Thread fit reduction |
The loss of thread precision caused by thick coatings such as hot dip galvanising.
Also known as: reduced thread tolerance Learn more → |
| Thread flank |
The angled surface between the crest and root of a thread that transmits load between mating fasteners.
Also known as: thread side |
| Thread run‑out |
The tapered end region of a thread where the profile fades out and full engagement is no longer possible.
Also known as: run‑out zone |
| Thread shear area |
The effective area of engaged threads that resists shear forces in a bolted joint.
Also known as: shear engagement area |
| Thread survey (Whitworth) |
Whitworth’s nationwide measurement of workshop thread forms to identify common patterns and propose a unified standard.
Also known as: Whitworth survey Learn more → |
| Thread tolerance class |
A designation defining the tolerance and deviation of internal and external threads, such as 6g or 6H.
Also known as: thread class |
| Thread vocabulary |
The standardised terminology used to describe fastener threads, geometry and features.
Also known as: fastener vocabulary |
| Threaded extraction pin |
A pin with an internal or external thread used to aid removal from interference‑fit assemblies.
Also known as: threaded pin |
| Threaded insert |
A metal insert with internal threads used to provide a durable fixing point in softer materials.
Also known as: insert nut |
| Threads per inch (TPI) |
A measure of thread pitch used in imperial fasteners, indicating the number of threads in one inch of length.
Also known as: TPI Learn more → |
| Thread‑cutting screw |
A screw designed to cut its own mating thread in materials such as metal or plastic.
Also known as: cutting screw |
| Thread‑forming screw |
A screw that forms internal threads by cold‑working the material rather than cutting it.
Also known as: form‑thread screw |
| Thread‑rolling screw |
A screw that displaces material to form internal threads without cutting, producing high‑strength load‑bearing threads.
Also known as: roll‑thread screw |
| Thread‑system fundamentals |
The basic principles that define how threads are specified, including pitch, angle, diameter and system family.
Also known as: thread basics Learn more → |
| Thumb screw |
A screw designed for hand tightening, typically with a knurled or winged head.
Also known as: hand screw |
| Tidy appearance |
A clean, uniform visual finish achieved using zinc plated or decorative screw heads.
Also known as: clean appearance, bright finish |
| TIGER mechanical fixing system |
A UK‑manufactured wall tie system using a stainless shaft and EPDM expansion sleeve for secure anchorage in masonry.
Also known as: TIGER wall tie system Learn more → |
| Tightening‑friction control |
The reduction and stabilisation of friction during tightening achieved by using a washer as a smooth interface.
Also known as: friction control |
| Timber applications (imperial) |
Uses of Whitworth or UNC threaded rod in timber structures where coarse threads provide strong engagement.
Also known as: timber fixings Learn more → |
| Timber battens |
Narrow timber strips commonly fixed using roof bolts in roofing and cladding applications.
Also known as: roof battens |
| Timber construction (bolts) |
Using bolts to secure timber components in structural or general‑purpose assemblies.
Also known as: timber bolting |
| Timber-based projects |
Construction or joinery projects using timber components secured with cup square bolts.
Also known as: timber projects |
| Timber‑construction bit performance |
The ability of a driver bit to maintain torque and resist cam‑out when driving screws into timber and studwork.
Also known as: timber‑grade bit performance |
| Tool engagement |
The quality of contact between a tool and the fastener head, affecting torque transfer and risk of cam‑out.
Also known as: drive engagement |
| Tooling compatibility (Whitworth family) |
The ability to use similar taps, dies and gauges across Whitworth‑based thread systems due to shared 55° geometry.
Also known as: Whitworth tooling compatibility |
| Tooling simplification (Unified) |
The reduction in required taps, dies and gauges achieved by adopting a single unified thread system.
Also known as: Unified tooling efficiency |
| Tool‑specific driver bit |
A driver bit manufactured to the exact length and shank profile required by a specific auto‑feed screw gun model.
Also known as: model‑specific driver bit Learn more → |
| Toothed lock washer |
A washer with serrations that bite into the mating surface to resist loosening under vibration.
Also known as: serrated washer |
| Torque‑control fine thread |
A fine‑pitch thread that allows more precise torque application due to smaller axial movement per turn.
Also known as: fine‑thread torque control |
| Torque‑transfer efficiency |
The ability of a driver type to transfer rotational force to the screw without slipping or deforming.
Also known as: torque efficiency |
| Toughness |
A material’s ability to absorb energy and resist fracture, especially after heat treatment.
Also known as: impact resistance |
| Trade‑grade 127 mm bit |
A professional‑quality PH2 driver bit with a 127 mm length, engineered for Makita 6833‑series auto‑feed tools.
Also known as: professional 127 mm bit Learn more → |
| Trade‑volume bulk bit supply |
Bulk quantities of 100 HELFAST driver bits supplied for contractors using Senco DS‑series tools in high‑volume environments.
Also known as: contractor bulk supply Learn more → |
| Trilobular screw |
A thread‑forming or thread‑rolling screw with a three‑lobed cross‑section that reduces driving torque and improves thread engagement.
Also known as: three‑lobed screw |
| Trivalent chromium |
A safer chromium compound used in modern zinc passivation systems, replacing hexavalent chromium.
Also known as: Chrome III Learn more → |
| T‑slot bolt |
A bolt designed to fit into T‑shaped machine table slots, allowing adjustable positioning in fixtures and clamping systems.
Also known as: T‑head bolt |
| T‑slot nut |
A rectangular nut designed to fit into T‑slots on machine tables and fixtures.
Also known as: T‑nut |
| UKCA approval (wall ties) |
Certification indicating that a wall tie meets UK regulatory requirements for construction products.
Also known as: UKCA certified Learn more → |
| UNC thread |
Unified National Coarse thread form used in imperial fasteners.
Also known as: Unified Coarse Learn more → |
| UNC thread system |
The coarse‑pitch series of the Unified Thread Standard, using a 60° V‑profile with flat crests and roots.
Also known as: Unified Coarse thread Learn more → |
| UNEF thread |
Unified National Extra Fine thread series used where maximum adjustment precision or thin‑wall engagement is required.
Also known as: Unified Extra Fine Learn more → |
| UNF thread |
Unified National Fine thread form used in imperial fasteners.
Also known as: Unified Fine Learn more → |
| UNF thread system |
The fine‑pitch series of the Unified Thread Standard, offering high tensile strength, precision and vibration resistance.
Also known as: Unified Fine thread Learn more → |
| Unified global metric system |
The worldwide adoption of ISO metric threads as the default standard for manufacturing and engineering.
Also known as: global ISO metric system Learn more → |
| Unified thread series |
The inch‑based thread system including UNC, UNF, UNEF, UN and UNR series.
Also known as: UN thread system Learn more → |
| Unique thread form (BA) |
A thread form with no interchangeability with Whitworth, BSF, BSW, UNC or UNF due to its metric basis and 47.5° angle.
Also known as: non‑interchangeable BA form Learn more → |
| Universal tie (starter application) |
A TIGER tie that can function as either a starter tie or a cavity tie depending on installation.
Also known as: dual‑purpose wall tie Learn more → |
| Universal wall tie |
A TIGER tie designed for both starter and cavity applications, with lengths suitable for a wide range of cavity widths.
Also known as: dual‑purpose wall tie Learn more → |
| Universal wall tie length range |
The available lengths of TIGER universal ties, covering a range of cavity widths and build-ups.
Also known as: TIGER tie length options Learn more → |
| Unpacked bulk supply |
Bulk quantities of driver bits supplied without retail packaging, typically in OEM bags for trade users.
Also known as: bulk OEM supply Learn more → |
| UNR thread |
A Unified thread variant with a mandatory rounded root to improve fatigue resistance.
Also known as: Unified rounded‑root thread Learn more → |
| UTS (Unified Thread Standard) |
A thread system established in 1948 covering UNC and UNF thread forms with a 60° angle.
Also known as: Unified Thread System Learn more → |
| Vanadium alloying |
The addition of vanadium to steel to improve strength, hardenability and fatigue resistance.
Also known as: vanadium addition |
| Vee‑thread |
A thread profile with straight flanks forming a V‑shape, used in most modern thread systems including Unified and ISO metric.
Also known as: V‑thread |
| Vehicles (imperial fasteners) |
Classic or older vehicles built using imperial thread forms that must be matched during maintenance or restoration.
Also known as: classic vehicles Learn more → |
| Vented screw |
A screw with a central hole or slot that allows trapped gases or fluids to escape during installation.
Also known as: vacuum vent screw |
| Vibration‑resistant thread |
A thread form whose finer pitch and increased engagement reduce the likelihood of loosening under vibration.
Also known as: anti‑vibration thread |
| Vibration‑resistant washer |
A washer designed to reduce loosening under vibration through mechanical locking or spring tension.
Also known as: anti‑vibration washer |
| Washer compatibility (imperial) |
Ensuring washers match the imperial thread form and diameter of the rod.
Also known as: imperial washer matching Learn more → |
| Washer for steel structures |
A washer designed for structural bolting, providing increased bearing area and controlled tolerances.
Also known as: structural washer |
| Washer hardness class |
The hardness rating of a washer, determining its suitability for use with high‑strength bolts.
Also known as: washer strength class |
| Washer-faced nut |
A nut with an integrated smooth bearing surface to improve load distribution.
Also known as: flanged nut |
| Washers |
Flat components used with nuts and threaded rod to distribute load and protect surfaces.
Also known as: flat washers Learn more → |
| Water installations |
Plumbing or water system installations where brass threaded rod is commonly used.
Also known as: plumbing installations |
| Wave spring washer |
A washer with a wavy profile that provides elastic preload in bolted joints.
Also known as: wave washer |
| Wave washer |
A spring washer with a wavy profile used to maintain light preload in assemblies.
Also known as: wave spring washer |
| Wedge‑locking washer |
A two‑piece washer system that uses cam faces to prevent loosening under vibration.
Also known as: cam‑locking washer |
| Whitworth standardisation |
The 1841 introduction of the first national thread standard, defining a 55° angle, fixed pitches and rounded crests and roots.
Also known as: Whitworth thread standard Learn more → |
| Whitworth thread |
A traditional British coarse‑pitch thread form used in older machinery and engineering.
Also known as: BSW, British Standard Whitworth Learn more → |
| Whitworth thread angle |
The 55° included angle used in BSW and BSF thread systems.
Also known as: 55° Whitworth angle Learn more → |
| Whitworth thread system |
The world’s first national screw thread standard, introduced in 1841 with a 55° angle and radiused crests and roots.
Also known as: Whitworth form Learn more → |
| Wing nut |
A nut with two protruding wings that allow tightening and loosening by hand without tools.
Also known as: thumb nut |
| Wing screw |
A screw with two protruding wings allowing tool‑free tightening and loosening.
Also known as: winged thumb screw |
| Wire rope clip |
A clamp used to secure wire rope terminations such as loops and thimble assemblies.
Also known as: rope clip, cable clip |
| Wire thread insert |
A helical wire coil installed into a tapped hole to create a wear-resistant internal thread.
Also known as: coil insert, helical insert |
| Woodruff key |
A semi-circular key used to transmit torque between a shaft and hub while accommodating slight misalignment.
Also known as: half-moon key |
| Workshop repairs (bolts) |
General mechanical repair tasks in workshop environments where hexagon set screws are commonly used.
Also known as: workshop maintenance Learn more → |
| X‑axis alignment |
The alignment of components along the primary horizontal axis in machinery or fixturing systems.
Also known as: horizontal axis alignment |
| X‑bracing |
A structural bracing pattern using crossed members to increase rigidity and resist lateral loads.
Also known as: cross‑bracing |
| X‑ray inspection |
A non‑destructive testing method used to detect internal defects in fasteners and structural components.
Also known as: radiographic inspection |
| Yellow zinc passivate |
A coloured passivation layer applied over zinc plating, giving a gold/iridescent finish with improved corrosion resistance.
Also known as: yellow passivate, gold zinc Learn more → |
| Yield point elongation |
The small strain region where steel exhibits a plateau in stress before work hardening begins.
Also known as: YPE Learn more → |
| Yield ratio |
The ratio of yield strength to tensile strength, indicating how much of the fastener’s capacity is usable before permanent deformation.
Also known as: yield proportion Learn more → |
| Yield strength |
The stress at which a fastener begins to deform plastically and can no longer return to its original shape.
Also known as: yield stress Learn more → |
| Zero‑clearance joint |
A bolted joint designed with minimal clearance between components to improve alignment and load transfer.
Also known as: tight‑fit joint |
| Zinc coating |
A protective zinc layer applied to steel fasteners to prevent corrosion.
Also known as: zinc plating, galvanized coating Learn more → |
| Zinc flake coating |
A non-electrolytic coating made from zinc and aluminium flakes, offering very high corrosion resistance without hydrogen risk.
Also known as: zinc flake system Learn more → |
| Zinc plating |
A thin electroplated zinc coating applied to steel fasteners to provide basic corrosion resistance in indoor or dry environments.
Also known as: electroplated zinc Learn more → |
| Zinc‑nickel plating |
A high‑performance electroplated coating containing 12–15% nickel, offering superior corrosion resistance compared to standard zinc.
Also known as: Zn‑Ni plating Learn more → |
| ± tolerance symbol |
A symbol indicating the permissible variation above or below a nominal fastener dimension.
Also known as: plus–minus tolerance Learn more → |
| Ø symbol (diameter) |
The symbol used on engineering drawings to indicate the diameter of a fastener or hole.
Also known as: diameter symbol Learn more → |
About this glossary
The terms and definitions on this page are created with the assistance of AI and reviewed by the FastenerFix team.
This glossary explains the words and phrases used across the FastenerFix website, along with selected general fastener terminology.
We aim for accuracy, but errors can occur. If you spot anything that needs attention, please contact us at
sales@fastenerfix.co.uk.