Special Fasteners
Special fasteners are non-catalogue bolts, screws, studs and nuts with unusual dimensions, head shapes, threads, materials or coatings, made to drawing. They are turned, cold-headed or hot-forged, threaded (often rolled), heat treated and finished to specification.
What it is
When a standard fastener won't fit, a special is manufactured: extra-long or short lengths, reduced shanks, special heads, collars, left-hand or fine threads, or exotic materials like duplex, Inconel or titanium.
Process choice depends on quantity: machining for small batches, cold heading or hot forging for volumes, with rolled threads for strength.
Typical applications
- Heavy machinery and equipment
- Oil, gas and petrochemical plants
- Automotive and railway
- Power plants and turbines
- Replacement fasteners for old machines
Materials & grades
- Carbon steel (4.6, 8.8, 10.9, 12.9)
- Stainless steel A2 (304) / A4 (316)
- Alloy steel (B7, high-tensile)
- Brass and non-ferrous
- Duplex, super duplex, Inconel, titanium
Points to consider
- Provide a drawing with thread class, head form and property requirements.
- Rolled threads are stronger than cut threads.
- Exotic materials need material certificates.
- Minimum order quantities vary by process.
Frequently asked questions
What makes a fastener 'special'?
Any non-standard feature: dimensions, head shape, thread form, material or coating outside catalogue ranges.
Can you make fasteners in small quantities?
Yes. Small batches are machined; larger volumes use cold heading or forging.
Are special fasteners heat treated?
Yes, to the property class or hardness specified, with test certificates on request.