Special Fasteners

Need a special fastener a distributor won't supply? If it's non-standard — an odd thread, a special head, an unusual length, an exotic material, or a part defined only by your drawing or an old sample — that's exactly what we manufacture, in small batches, without a tooling bill.

What Is a Special Fastener?

A special fastener is any fastener that isn't a standard catalogue item. In practice that means one or more of: a non-standard thread or pitch, a special head or drive, an unusual length or diameter, a shoulder or stepped form, an exotic material, or simply a part made to your own drawing. The moment a distributor says "non-stock" or quotes a five-figure minimum, you're looking at a special — and that is the whole of what we do.

EKINSUN manufactures special fasteners to your drawing, specification or physical sample, in low to medium volumes, with a quote back within 12 hours. We are a manufacturer, not a stockist: if a standard part covers the job a distributor will always be cheaper, and we'll tell you so. When it doesn't exist off the shelf, that's what we're for.

Special vs Standard — Where the Line Is

Standard (buy off the shelf)	Special (we manufacture)
Common metric / UNC / UNF sizes	Non-standard threads, odd pitches, BSW/BSF/BA
Standard hex / socket heads	Special heads, drives, shoulders, stepped forms
Catalogue lengths	Any length, oversize or extra-long
Carbon & basic stainless	Duplex, Inconel, Monel, Hastelloy, titanium
Bulk quantities	1 piece to medium batch, no tooling cost

Special Fasteners We Manufacture

Special Heads, Drives & Forms

Often what makes a fastener "special" isn't the thread at all — it's the head, the drive or the shank. We machine forms that stock ranges don't carry:

• Heads: oversize and reduced hex, cheese, pan, countersunk, dome, square, T-head, hammer/eye and collar heads.
• Drives: socket (Allen), Torx, slotted, one-way and tamper-resistant/security drives.
• Shanks: shoulder and stepped bolts, waisted (reduced-shank) bolts, part-threaded and fully threaded, drilled for lockwire or split pins.
• Nuts: castle, slotted, cap/dome, coupling, thin and heavy-pattern in non-standard across-flats.

If your drawing calls out a head or drive nobody stocks, send it — head geometry is machined to your dimensions like any other feature.

Two special families busy enough to earn their own pages: custom U-bolts bent and threaded to your exact inside width, and banjo and hollow bolts with the bore, ports and restrictor drilled to spec.

Materials & Grades

Family	Grades we machine	Typical use
Stainless	A2/304, A4/316, 303, 17-4PH	Corrosion resistance, marine, general special work
Duplex	Duplex & super duplex (e.g. 2205, 2507)	Chloride/seawater, high strength + corrosion
Nickel alloys	Inconel, Incoloy, Monel, Hastelloy	High temperature, aggressive chemical, oil & gas
Titanium	Grade 2, Grade 5 (Ti-6Al-4V)	Strength-to-weight, aerospace, motorsport
Alloy & high-tensile steel	Class 8.8 / 10.9 / 12.9, EN24T	Load-bearing, structural, machinery
Brass, bronze, plastics	Brass, aluminium bronze, PEEK, PTFE	Electrical, low-friction, non-magnetic, insulating
Aluminium	6061-T6, 7075-T6	Weight-critical, lightly loaded parts only — aluminium threads strip long before steel, so for a loaded fastener we usually point you to titanium or class 8.8 instead

Material certification to EN 10204 3.1 is available on request, with dimensional inspection to your drawing. Our manufacturing partners are ISO 9001:2015 certified. If your application needs a specific approval scheme, tell us the requirement before ordering so we can confirm exactly what we can certify.

Manufacturing Capability

Feature	Typical range
Diameter	M2 – M64 (and imperial 1/8" – 2.1/2")
Length	A few mm to 600 mm+ (extra-long by arrangement)
Threads	Metric, UNC/UNF/UNEF, BSW/BSF/BA, BSP, ACME, left-hand, odd pitches
Tolerance	To your drawing; thread & diameter typically to standard class or tighter
Finish	Plain, black oxide, zinc, passivation, PTFE/Xylan coatings
Quantity	1 piece to medium batch — no tooling charge

Industries We Supply

Special fasteners made to drawing go into demanding, low-volume applications where a catalogue part won't do:

• Oil, gas & petrochemical — duplex and nickel-alloy studbolts and specials for corrosive service.
• Marine & offshore — 316, duplex and titanium fasteners for saltwater exposure.
• Machinery & heavy engineering — special bolts and studs for rebuilds and OEM assemblies.
• Motorsport & automotive — titanium and high-tensile specials, odd threads, weight-critical parts.
• Restoration & heritage — Whitworth and BSF specials and obsolete fasteners reproduced from a sample.

How It Works

Special Fasteners According to Drawing — Supplying the UK

Enquiries from the UK usually arrive the same way: special fasteners according to drawing — the drawing is finished, the quantity is small, and the local quote is slow or carries a minimum. That is the workflow this whole page describes, and supplying it to the UK is routine:

• Quote within 12 hours of your drawing, with every quantity tier priced upfront.
• 3–4 business days in transit to the UK — DHL or FedEx, tracked door to door.
• DDP terms on request — the quoted price then includes UK import duty and VAT clearance, so the courier collects nothing at the door.
• Quotes and invoices in GBP, paid to a GB bank account — no currency conversion on your side.
• Legacy imperial callouts machined like any metric thread — BSW, BSF and BA cut alongside metric, UNC/UNF and BSP.

What that looks like in practice: a machine builder in the UK sent one PDF of their own drawing — a one-off clamp coupling in 316 stainless, bore inspected to H7 — and got a fixed all-in price against that drawing and the finished part in about 5 working days. The full story is in the one-off coupling case.

Who Actually Makes a Special Fastener

Ask who manufactures special fasteners and three quite different kinds of company answer, which is why quotes for the same drawing can come back an order of magnitude apart.

A cold-heading works forms the part between dies. It is how almost every standard bolt in the world is made, and it is very good at that — but the dies have to exist first. For a shape nobody has run before, someone has to pay for them, and that is where the five-figure minimum in your inbox comes from. Below a few thousand pieces the tooling dominates the price completely.

A machine shop turns the same part from bar. There is no die, so the geometry is a program and the first piece costs close to what the hundredth does. That is the trade: a worse per-piece price once the volume is large, and the only sensible answer at one to a few hundred. That is what we are.

A distributor holds stock. Ask for something outside it and you will usually get a polite no, or a long wait while they look for someone in the first two categories. That is not a criticism — for anything that already exists, a good distributor is the cheapest route by far.

So the honest way to place the job is by quantity, not by preference. If you need ten thousand of one shape for years, find a heading works and pay for the dies. If you need four, or forty, or a hundred and forty, machining from bar is not a compromise — it is the correct process for that number.

Where the Catalogue Stops

What you need	Off the shelf?	What we actually do
M8×40 socket cap screw in A2 stainless	Yes, stocked	Buy it. A stocked size will always beat a machined one on price, and we would rather say so than take the order.
Ten thousand of one standard shape, every year	Yes	Go to a heading works. At that quantity the dies pay for themselves several times over and we cannot get near the price.
A pitch that is not in any table — or a thread that predates the metric system	No	Single-point turned to the pitch on your drawing, including Whitworth BSW and BSF at the 55° form for pre-war and British machinery.
A head or drive nobody lists — low head, wide flange, wrench flats to suit the space you have	No	Milled to the access you actually have, rather than to a table drawn up for open assembly.
A shoulder or a stepped shank with a toleranced bearing diameter	Rare	Shoulder and thread cut in one setup, so the bearing diameter stays concentric with the thread — something a stack of standard parts cannot promise.
17-4PH, duplex or titanium in a quantity nobody wants to break a bar for	Rare	Bar bought in for the job. Material is a small part of the cost of a machined fastener; the machine time is the cost.
A fastener carrying a nuclear or safety-critical qualification	From a qualified house	Not us. The qualification is the product in that trade, and we do not hold it.
One replacement for a machine whose maker has gone	No	Copied from the worn original, with worn diameters taken back to the original nominal rather than to what is left of them.

Frequently Asked Questions