Prevailing-Torque Locknuts

Nov. 15, 2002
A built-in locking feature develops full locking action as soon as these nuts are engaged with the bolt threads.

A built-in locking feature develops full locking action as soon as these nuts are engaged with the bolt threads. They must then be wrenched to final seated position.

Several of the locking techniques rely on a distortion of the nut thread or shape to create an interference fit. Metal or nonmetal inserts (plugs, strips, or collars) that plastically deform are also used to create an interference fit. Sometimes, separate locking pins, wires, or springs are fitted to the nut, or the nut may have a large slotted crown with springlike fingers that grip the bolt.

Ideally, prevailing-torque nuts should be used with the minimum thread engagement necessary to develop the holding strength of the nut and the locking action. Torquing these nuts over a long thread travel under load could damage the locking feature.

Prevailing-torque locknuts can also be used as spacer or stop nuts where components must be free to rotate without end play.

Sponsored Recommendations

June 27, 2025
Ensure workplace safety and compliance with our comprehensive Lockout/Tagout (LOTO) Safety Training course. Learn critical procedures to prevent serious injuries.
June 27, 2025
Join our expert webinar to discover essential safety control measures and best practices for engineering a truly safe and compliant industrial environment.
June 25, 2025
An innovative aircraft with electric drives combines the best of both worlds. The cross between drone and helicopter could mean significantly faster and more efficient air emergency...
June 25, 2025
Effective when other materials fail, ceramics are particularly suitable for applications requiring wear and chemical resistance, sliding characteristics or biocompatibility. Discover...

Voice your opinion!

To join the conversation, and become an exclusive member of Machine Design, create an account today!