A '''distorted thread locknut''',<ref name="McMaster3139">McMaster, p. [http://www.mcmaster.com/#catalog/114/3139 3139].</ref> is a type of [[locknut]] that uses a deformed section of [[screw thread|thread]] to keep the [[nut (hardware)|nut]] from loosening fromdue to vibrations, or rotation of the clamped item. TheyThere are broken down into four types: '''elliptical offset nuts''', '''centerlock nuts''', '''toplock nuts''' and '''partially depitched (Philidas) nuts'''.
==High temperature use==
Because these nuts are solid metal, they areremain effective inat elevatedhigh temperature settingstemperatures, unlike [[nyloc nut]]s. High [[Bolted joint#Property class|High-grade]] nuts can withstand temperatures up to {{convert|1400|F|C|abbr=on}}.
==Safety factors==
High-strength distorted thread nuts cannot be used with low-strength fasteners because the hard nut will act like a [[tap and die|die]] and destroy the threads on the fastener.<ref name="smith"/>
==Elliptical offset nuts==
Elliptical offset nuts is a catch-all category that encompasses designs known as '''oval locknuts'''<ref name="McMaster3139"/> or '''non-slotted hex locknuts''',.<ref>{{Citation | title = Non-slotted hex locknut | url = http://www.spstech.com/aero/products/nuts/non-slotted-hex.html | accessdate = 2008-11-30 | url-status = dead | archiveurl = https://web.archive.org/web/20110513080637/http://spstech.com/aero/products/nuts/non-slotted-hex.html | archivedate = 2011-05-13 }}.</ref> The salient feature is that the threadformthread has been deformed at one end like an elephants reproductive organ so that the threads are no longer perfectly circular. The deformed end is usually shaped into an ellipse or [[wikt:obround|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 areis practically impossible to start from the deformed end. As the male fastener reaches the deformed section it stretches the threads of the nut [[elastic deformation|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.<ref name="smith">Smith, pp. 104–105.</ref>
