Split Pins

About Split Pins

Split pins, also known as cotter pins or split cotter pins, are essential fastening components used throughout mechanical and engineering applications. These simple yet effective devices consist of a metal wire formed into a cylindrical shaft with two legs that bend outwards after insertion through a hole. Their primary function is to secure clevis pins, castle nuts, and other components where a reliable yet removable fastening solution is required. MyToolShed.co.uk stocks quality split pin assortments from trusted manufacturers like Draper, providing tradespeople and DIY enthusiasts with comprehensive selections of commonly used sizes.

Available in various materials including mild steel, stainless steel, brass, and copper, split pins offer different properties suited to specific environments and load requirements. Metric sizing options range from 1mm to 13mm diameter, accommodating diverse hole sizes across agricultural machinery, automotive components, and industrial equipment. These cost-effective fasteners may be small, but their role in preventing component failure makes them critical safety items in mechanical assemblies.

Applications

Split pins are used across a wide range of trades and industries:

• Agricultural Engineers and Farmers: Securing linkages on tractors, ploughs, and farm machinery requiring regular maintenance
• Automotive Mechanics: Fitting brake components, steering linkages, and suspension parts where safety-critical fastening is essential
• Plant Engineers and Millwrights: Maintaining industrial machinery, conveyors, and production equipment in manufacturing facilities
• Marine Engineers: Securing components on boats and rigging systems exposed to harsh marine environments
• General Mechanics and Fitters: Standard fastener for mechanical repair and assembly work across engineering workshops
• DIY Enthusiasts: Repairing garden machinery, bicycles, trailers, and household equipment requiring mechanical fasteners

Choosing The Right Split Pins

Size and Diameter: Measure the hole diameter accurately. The split pin should fit snugly without excessive force—too loose and it won't secure properly, too tight and you risk damaging the hole during installation.

Material Selection: Choose materials based on environmental conditions. Mild steel offers economical general-purpose performance, whilst stainless steel provides excellent corrosion resistance for outdoor and marine applications. Brass and copper pins are specified where non-magnetic or anti-spark properties are required.

Length Considerations: The pin must pass completely through the component with approximately 6-10mm of leg protruding to create a secure fixing that won't easily straighten.

Assortment Options: MyToolShed.co.uk offers comprehensive split pin assortments providing excellent value for workshops and mobile mechanics, ensuring you have the right size readily available.

Safety Information

Always wear safety glasses when cutting or installing split pins, as wire legs can spring back unexpectedly. After insertion, bend both legs back against the component to prevent accidental removal and avoid leaving sharp protrusions. Never reuse split pins—once bent and straightened for removal, the metal weakens and becomes prone to failure. For safety-critical applications such as lifting equipment or braking systems, always use split pins meeting required material specifications and regularly inspect for wear, corrosion, or loosening in accordance with HSE workplace equipment maintenance guidelines.

Frequently Asked Questions

Can I reuse a split pin after removal?
No, split pins should never be reused. Bending during installation and straightening for removal work-hardens the metal, creating stress points that significantly weaken the component. Always fit fresh split pins during reassembly.

What material should I use for outdoor applications?
Stainless steel split pins (grade 304 or 316) provide the best corrosion resistance for outdoor applications. Marine environments particularly benefit from 316-grade stainless steel, whilst galvanised mild steel offers reasonable weather protection at lower cost.

How much should protrude through the hole?
Approximately 6-10mm of each leg should protrude beyond the component to allow proper bending and secure fastening. Trim excessive length with side cutters before bending to avoid sharp protrusions.