Lock 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 insert that resists turning.
The plastic insert is placed at the end of the nut, with an inner diameter (ID) slightly smaller than the major diameter of the screw. The insert deforms elastically over the threads of the screw, without having threads in turn cut into it. The nylon insert locks the nut by friction against the screw under the applied radial compressive force. Nyloc nuts retain their locking ability up to 250 °F (121 °C)
Are also known as half-thickness nut or a split nut; these are used as a locknut or jam nut.
Often used in pairs or in conjunction with a hexagon full nut in a locking arrangement.
- Standards : DIN 439, ISO 4035
- Materials: Mild Steel and Stainless Steel – AISI-304 and AISI-316
The thin nut must be put in place first and the full nut after that.
The thin lock nut should be used first and tightened to between 25% to 50% of the overall required torque.
The thin nut is then held in place while the second thicker nut is then installed and tightened to full torque.