Keps Nut

A keps nut is a hex nut with a captive toothed washer that grips the surface as it is tightened. The washer resists loosening from vibration.

A keps nut has a captive washer that stays on the nut. It suits assembly work where the washer must not be lost or dropped. It takes a bolt of the same thread and is run down with a spanner or socket.

Keps nuts are often made in steel with a plated finish. The captive washer is usually spring steel.

This is a general guide to checking this kind of part. It says nothing about any supplier's parts.

Ask for a certificate of conformance and check the washer is captive and turns freely. On receipt, check the thread and the washer teeth.