Nylon Insert Lock Nuts

A hexagon nut with a nylon collar in the top, to DIN 985 and ISO 10511. The bolt cuts its own path through the collar, and the friction that creates holds the nut in place independently of clamp load. This is what the standards call prevailing torque.

Why prevailing torque beats friction

A plain nut holds only while the joint stays tight. Let the clamp load drop — thermal cycling, settling, vibration — and it walks off. A nylon insert keeps gripping at zero clamp load, which is why it is the default on anything that moves.

Limits worth knowing

The nylon is good to roughly 120 °C and no higher. It is also not designed for repeated use: each cycle cuts the collar further, and after three or four removals the locking action is largely gone. Treat them as consumable.

The bolt must protrude fully through the nylon or the locking feature does nothing at all — a nut run on only to the top of the metal section is just a plain nut.

Material

304 stainless body, natural nylon insert. For non-vibrating joints, a plain hex nut is cheaper and easier to service.