How to Install Cotter Pins

A cotter pin is a split wire fastener used to connect two pieces of metal. The metal parts are joined with one end containing a hole for the cotter pin. The pin is inserted though the hole to fasten the parts together. Cotter pins are commonly found on the end of an axle for a walk-behind lawnmower. The wheels slip over the axles, which have drilled holes in the ends for cotter pins to hold the wheels in place.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Needle-nose pliers

1. Connect the parts to be secured by a cotter pin. For example, a wheel slips onto the end of an axle, leaving the cotter pin hole exposed at the end of the axle.

2. Insert the two tines of the cotter pin through the hole until the eye of the cotter pin is flush against the hole.

3. Pry apart the two tines at the end of the cotter pin using the needle-nose pliers. Bend each tine upward so that the pin cannot pull out on its own.

4. Make sure the cotter pin is not obstructing the movement of the two parts.

References

• Cotter Pin Types and Information
• Photo of Cotter Pin Installation