Products + Tools

PEM® Type SL™ self-clinching steel lock nuts, from PennEngineering®, integrate a unique TRI-DENT® locking feature that provides sufficient torsional resistance to withstand vibration, thermal cycling, and other disruptive forces that could loosen the screws in service.

These prevailing torque lock nuts, which meet 3 cycle locking performance to effectively ‘self-lock’ the threads of mating screws, will also enable the screws to be removed and reattached repeatedly as needed without compromising the locking threads.

PennEngineering says these lock nuts install permanently in host metal sheets to become integral parts of an assembly – they will not loosen or fall out; never have to be restrained from rotation with a tool; and never have to be handled again. Compared with conventional chemical adhesives or affixed patches, the lock nuts can help save time and money during production by minimising the number of required assembly steps and materials.

PEM Type SL lock nuts are available in thread sizes #4 – 40 through 3/8 – 16 and M3 through M10. They are recommended for use in aluminium or steel sheets as thin as 0.04 inches/1mm with maximum hardness HRB 80 (Rockwell ‘B’ scale) and HB 150 (Hardness Brinell).

Quick installation is accomplished by placing the lock nut in a properly sized mounting hole and applying sufficient squeezing force using a standard press to embed the fastener’s clinching ring completely in the metal sheet. All clinching is performed on the fastener side of the sheet, allowing the reverse side to remain flush and smooth without protrusions.