A distorted thread locknut,McMaster, p
3139
is a type of

locknut A locknut, also known as a lock nut, locking nut, self-locking nut, prevailing torque nut,. stiff nut or elastic stop nut, is a Nut (hardware), nut that resists loosening under vibrations and torque. Prevailing torque nuts have some portion of ...

that uses a deformed section of thread to keep the

nut Nut often refers to: * Nut (fruit), fruit composed of a hard shell and a seed * Nut (food), a dry and edible fruit or seed, including but not limited to true nuts * Nut (hardware), fastener used with a bolt Nut, NUT or Nuts may also refer to: A ...

from loosening due to vibrations, or rotation of the clamped item. There are four types: elliptical offset nuts, centerlock nuts, toplock nuts and partially depitched (Philidas) nuts.

High temperature use

Because these nuts are solid metal, they remain effective at high temperatures, unlike

nyloc nut A nyloc nut, also referred to as a nylon-insert lock nut, polymer-insert lock nut, or elastic stop nut, is a kind of locknut with a nylon collar that increases friction on the screw thread. The nylon collar insert is placed at the end of the nut, ...

s. High-grade nuts can withstand temperatures up to .

Safety factors

High-strength distorted thread nuts cannot be used with low-strength fasteners because the hard nut will act like a

die Die, as a verb, refers to death, the cessation of life. Die may also refer to: Games * Die, singular of dice, small throwable objects used for producing random numbers Manufacturing * Die (integrated circuit), a rectangular piece of a semicondu ...

and destroy the threads on the fastener.

Elliptical offset nuts

Elliptical offset nuts is a catch-all category that encompasses designs known as oval locknuts or non-slotted hex locknuts,. The salient feature is that the thread has been deformed at one end so that the threads are no longer perfectly circular. The deformed end is usually shaped into an ellipse or obround triangle. These are known as one-way nuts as the nut may be easily started on the male fastener from the bottom non-deformed portion but is practically impossible to start from the deformed end. As the male fastener reaches the deformed section it stretches the threads of the nut elastically back into a circle. This action increases the friction between the nut and the fastener greatly and creates the locking action. Due to the elastic nature of the deformation the nuts can be reused indefinitely.Smith, pp. 104–105.

Centerlock nuts

Center lock nuts are similar to elliptical offset nuts, except that they are distorted in the middle of the nut. This allows the nut to be started from either side.

Toplock nuts

Toplock nuts are also similar to elliptical offset nuts, except that the whole thread on one end is not distorted. Instead only three small sections of the thread are deformed on one end.

Partially depitched nuts

Partially depitched nuts are commonly called Philidas nuts,. after their originator and current manufacturer, and differ from the above three nut types insofar as a portion of the thread is displaced axially, this being facilitated by one or more slots perpendicular to the axis.

References

Notes

Bibliography

*. *. {{Nuts (hardware) Nuts (hardware)