Split Cotter Pins (ISO 1234 / DIN 94) are specified where the joint requires precise location and light shear duty between two parts. The sections below cover the typical end-uses by industry, the size and material decisions for each, assembly practice, and the applications this fastener type is not suited to. Stocked across roughly M0.6 to M13, they cover general to heavy-duty work.
Typical Applications for Split Cotter Pins
The most common settings where these are specified:
- Jigs & fixtures: precise location of tooling plates and locating features.
- Linkages & hinges: pivot points carrying light shear.
- Machine alignment: dowelling mating housings so they reassemble in the same position.
- General machine building: fastening covers, brackets, motors and sub-assemblies on production equipment.
- Maintenance & repair (MRO): a stocked size for servicing existing plant where the original fastener spec must be matched.
How to Specify Split Cotter Pins for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M0.6–M13; check the full table below for the exact dimensions of each size.
- Material: Choose the material and finish for the service environment — plated steel for general use, stainless for corrosion resistance.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to ISO 1234 / DIN 94. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Installation & Assembly Practice
- Ream the hole to the specified fit class; a dowel pressed into a drilled-only hole will not locate accurately.
- Press pins in with steady force rather than hammer blows where possible, and chamfer the hole entry.
Common Selection Mistakes with Split Cotter Pins
- Using a dowel pin as a load-carrying shear bolt — dowels locate, they are not sized for sustained shear.
- Ignoring the fit class: a locational fit and an interference fit need different hole tolerances.
Where Split Cotter Pins Are Not the Right Choice
Not for carrying significant tensile or repeated heavy shear loads — use a bolt or a keyed joint for that.