Hammerlock Cotter Pins

Hammerlock Cotter Pins

Hammerlock cotter pins, commonly referred to as castle keys or castle nut cotters, are wire formed locking mechanisms often used for securing castle nuts in high vibration applications. A castle nut is tightened onto a threaded shaft or bolt and then the cotter pin is driven through a drilled hole in the shaft that aligns with the grooves in the nut. As the pin is driven though, the prongs are forced apart, and the pin locks into place preventing the nut from loosening. These cotter pins are popular in the automotive and trailer industries to help hold wheel bearings in place. Hammerlock cotter pins are permanently deformed during installation and are not reusable.