R-Clips (Hair Pin Cotters)
R-clips - also called hair pin cotters or R-pins - are bent spring wire retainers shaped like the letter R: one straight leg passes through a cross-hole in the shaft while the bowed leg springs over the shaft's outside. Fitting and removal are by hand, with nothing to bend or cut. We supply them in zinc plated spring steel with many sizes also made in stainless steel, available across a range covering shaft diameters from 4mm to 65mm.
Also known as: r clip, r pin, hair pin cotter, hairpin cotter, hitch pin clip, spring cotter pin, retaining pin, din 11024.
Materials & strength
Sprung grip, tool-free fitting
The bowed leg deflects as the clip is pushed on and then grips the shaft surface, holding the straight leg in its hole. Pulling the clip back off is a one-hand job, and the clip is designed for repeated removal and refitting - replace it if the wire shows signs of fatigue, permanent deformation or reduced spring tension.
Sizing by shaft and wire
Clips are specified by the shaft diameter band they fit and the wire gauge they are bent from. The shaft hole should be sized to accept the wire diameter with enough clearance to insert and seat the clip securely — confirm the hole size from the clip manufacturer's fitting data.
Double-coil and safety patterns
A double-coil variant closes the head into a full ring - safer for attaching a lanyard and springier across a wider size band. Safety-pin style clips latch closed right around the shaft for the larger diameters.
Related specificationsWhat size R-clip do I need?
Match the clip to the shaft diameter first - each clip serves a band of shaft sizes - then check the cross-hole suits the wire gauge. If the application is borderline between two sizes, the larger wire gives the firmer grip.
R-clip or split pin?
A split pin makes a semi-permanent lock - bent to fit and renewed at each strip-down. An R-clip trades some security for speed: no tools, instant removal, repeated reuse - replace the clip if the wire shows fatigue, permanent deformation or reduced spring tension. For pins and shafts that are disturbed regularly, the R-clip is the practical choice.
Do R-clips follow a standard?
There is little national standardisation for these clips - the shapes are made to established factory patterns, with UK and continental bow forms both current.
Are stainless R-clips available?
Yes - a good proportion of the size range is made in stainless steel, in A2 or A4 grade depending on size, as well as zinc plated spring steel.
Need R-clip in a non-standard size or material?
Send us your drawing — specials quoted within 24 hours.