Distorted thread locknut

A distorted thread locknut,^[1] is a type of locknut that uses a deformed section of thread to keep the nut from loosening from vibrations or rotation of the clamped item. They are broken down into three types: elliptical offset nuts, centerlock nuts, and toplock nuts.

Because these nuts are solid metal, they are effective in elevated temperature settings, unlike nyloc nuts. High grade nuts are good up to 1,400 °F (760 °C). High strength distorted thread nuts cannot be used with low strength fasteners because the hard nut will act like a die and destroy the threads on the fastener.^[2]

Elliptical offset nuts

Elliptical offset nuts, also known as oval locknuts^[1] or non-slotted hex locknuts,^[3] is a nut that 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. The nut is easily started on the male fastener as the bottom portion is not deformed. As the male fastener reaches the deformed section it deforms 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.^[2]

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.^[1]

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.^[1]

See also

• Split beam nut

References

Notes

1. ^ ^{a b c d} McMaster, p. 3139.
2. ^ ^{a b} Smith, pp. 104–105.
3. ^ Non-slotted hex locknut, http://www.spstech.com/aero/products/nuts/non-slotted-hex.html, retrieved 2008-11-30 .

Bibliography

• McMaster-Carr catalog (114th ed.), McMaster-Carr .
• Smith, Carroll (1990), Carroll Smith's Nuts, Bolts, Fasteners, and Plumbing Handbook, MotorBooks/MBI Publishing Company, ISBN 0879384069, http://books.google.com/?id=A81HmmRCN7YC .