PEM self-clinching locknuts prevent mating hardware from loosening. LN SELF-LOCKING FASTENERSSELF-LOCKING FASTENERS PEM SELF-CLINCHING LOCKNUTS PREVENT MATING HARDWARE FROM LOOSENING PEM self-clinching locknuts provide ideal solutions to prevent mating hardware from loosening in service due to vibration or other application-related factors. This family of fasteners includes a variety of types and different locking- feature styles to satisfy a wide range of applications. Their use can save time and money compared with alternative chemical locking methods or patches. ABOUT LOCKING THREADS PEM locknuts include two locking designs: 1) PREVAILING TORQUE (CFN, FE, FEO, UL, LAS, LAC, LA4, LK, LKS, LKA, PL, PLC and SL locknuts) a design feature of the lock nut produces friction between threads of mated components thereby increasing the force needed to tighten as well as loosen the nut. Prevailing torque locknuts provide essentially the same torque value regardless of the amount of axial load applied. Available in two types: All metal All PEM metal prevailing torque type locknuts achieve their prevailing torque by altering the shape of the nut in some way - most commonly by distorting the threads of the nut, which then grips the mating part during tightening. Screws for use with PEM prevailing torque locknuts should be Class 3A/4h fit or no smaller than Class 2A/6g. Available in three styles: Elliptically squeezed threads (UL, FE, FEO, LAC, LAS and LA4 locknuts) the thread barrel is slightly deformed into an elliptical shape. Flexing jaws (LK, LKS and LKA locknuts) - the thread barrel is vertically slit and then the two sections are squeezed together. One or two deformed threads (SL locknuts) - the last threads on the head side of the nut are deformed. Typically prevailing torque locknuts utilizing a metal locking feature are treated with a dry film lubricant coating to aorff d some level of lubricity to reduce damage to the threads from repeated installation and removal of the screw and reduce required tightening torque.Care should be taken to be sure that lubricant is not removed in any post installed finishing operations. Nylon insert The PL, PLC and CFN locknuts use a plastic insert, typically made from nylon to generate the torque resistance.A nylon ring is attached to the self-clinching body on the screw exit side with an ID approximately at the screw pitch diameter. As the screw enters this ring, there is interference at the major diameter generating a prevailing torque. The major advantage of this locking method is the greatly reduced chance of any conductive debris being generated by repeated installation and removal of the screw. 2) FREE-RUNNING (PEM RT locknuts) a nut that requires tightening against a bearing surface in order for the locking mechanism to function. If the tightening force (clamp load) is removed for any reason, these nuts no longer provide any torsional resistance to rotation. The modified thread formation allows mating screws to spin freely during the attachment process until clamp load is induced during the screw-tightening process. PEM free-running locknuts will accept a maximum material 6g/2A screw. Fastener drawings and models are available at www.pemnet.com LN-2 PennEngineering www.pemnet.com 2021 PennEngineering.