Elliptical offset nuts,alsois 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}}.</ref>. isThe asalient nutfeature is that the threadform 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 [[wikt:obround|obround]] triangle. TheThese are known as '''one-way''' nuts as the nut ismay be easily started on the male fastener asfrom the bottom non-deformed portion, isbut notare practically impossible to start from the deformed end. As the male fastener reaches the deformed section it deformsstretches 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>
Oval locknuts per the McMaster reference<ref name="McMaster3139"/> are also known as Stover Nuts<ref name="FastenerExperts"/>
