Studs and threaded bar are where NAB and SAB fasteners most often depart from the catalogue — a flange studbolt with two nuts, a metal-end stud into a valve body, an engineering stud with a plain shank between two different thread lengths, or threaded bar cut to length. We machine all of them from certified bar with machined threads, to BS 4439, BS 4882 forms, DIN 976, or your drawing, in nickel aluminium bronze (CuAl10Ni5Fe4 — CW307G / CA104) and aluminium silicon bronze (CuAl6Si2Fe — CW301G / CA107). BS 4439 covers M3 to M39; our supply range is M8 to M52 subject to review, with smaller and larger to drawing and imperial from 1/4". Supplied with material certification and, where specified, to NES 833 / DEF STAN 02-833 for NAB, NES 834 / DEF STAN 02-834 Pt 2 (superseded by 02-879 Pt 2 Annex D, Sept 2011) for SAB, and the DEF STAN 02-862 Part 2 manufacturing route. No minimum order quantity.
There's no single dimension table for studs — the geometry is set by the standard or the drawing. What matters is which form you need and the three lengths that define it.
| Form | Standard | Description | What to give us |
|---|---|---|---|
| Metal-end stud | BS 4439 (M3–M39) | One end screwed permanently into the parent metal (metal end), the other takes a nut. The metal-end thread uses the specified close-fit or oversize form; for DEF STAN 02-862 metric studs the default metal-end tolerance is 4h unless the contract or drawing states otherwise | Thread size, overall length, metal-end thread length (BS 4439 offers a choice by housing material), nut-end thread length |
| Double-end stud | Drawing / applicable product standard | Threaded at both ends with a plain shank between, normally used with a nut or threaded component at each end; thread lengths equal or unequal as specified | Thread size, overall length, thread length each end |
| Studbolt | BS 4882 forms (form and length reference only — BS 4882 materials are steels; the material is the bronze specification on the drawing) | A fastener threaded at both ends or throughout its length, used with nuts at both ends, for flanged joints and pressure equipment; BS 4882 includes full-thread and plain/reduced-shank forms. For DEF STAN 02-862 Part 2 metric studbolts the dimensional call-up is BS 4882 Figure 1b unless the drawing specifies otherwise | Thread size, overall length, nut form, whether chamfered or rounded ends |
| Engineering stud (stepped) | Drawing | Three specified sections — short thread, plain shank, long thread — often with different lengths each end and a shoulder or waist | Drawing, or the three lengths plus shank diameter |
| Shouldered / waisted stud | Drawing | Plain shank reduced below the thread minor diameter for fatigue performance, or a shoulder for location | Drawing |
| Threaded bar (allthread) | DIN 976-1 (replaced DIN 975) | Fully threaded bar; common standard lengths 1 m, 2 m and 3 m, subject to material and manufacturing review, or cut to size | Thread size, length, quantity of cut pieces |
Imperial (UNC / UNF / BSW / BSF), left-hand, multi-start and combination threads to drawing — see Made to Drawing.
CuAl10Ni5Fe4. The higher-strength alloy, with excellent seawater, erosion and cavitation resistance; commonly specified for structural and immersed fastenings. Naval material standard NES 833 / DEF STAN 02-833 Part 2. Relative magnetic permeability typically around 1.4–1.5. Full data, designations and cross-references on the NAB material page.
CuAl6Si2Fe. Good machinability, ductile, and formulated for controlled low magnetic permeability — relative magnetic permeability not exceeding 1.05 (DEF STAN 02-879 Part 2 Annex D, D.2.8; batch-tested to D.4.5) — used for mine countermeasures vessels and other naval low-signature applications. Tighter permeability limits are a drawing or contract requirement and are handled at enquiry stage. Naval material standard NES 834 / DEF STAN 02-834 Part 2, subsequently incorporated into DEF STAN 02-879 Part 2 Annex D. Full data on the SAB material page.
Source-material certification supplied as standard, with traceability to the bar heat maintained through manufacture. Where the drawing calls for DEF STAN 02-862 Part 2, studs and studbolts are machined from bar with machined threads and post-machining stress relief per clause 8.2.4 (NAB) or 8.2.5 (SAB), with heat treatment and stress relief records supplied where required by the drawing, specification or purchase order. Marking, EN 10204 3.1 certification, dimensional inspection reports and CoC as required by the order; EN 10204 3.2 where agreed in advance and supported by the material source and inspection arrangements.
The drawing and specification govern. Alloy designations above are cross-references, not statements of equivalence.
Stepped, shouldered, metal-end, imperial, or an odd length — upload it and we'll quote within 24 hours.
Send us your drawing or spec reference and we'll come back with a price and lead time. No minimum order quantity.