Press

Pemhex is a self-clinching prevailing torque lock-nut from Penn Engineering, with the integrated nylon insert there to resist screw loosening in service due to vibration and thermal cycling.

“The reusable locking element provides the necessary torque resistance to securely grip mating screws and allow for their repeated installation and removal over time,” said Penn. “The primary advantage of this locking method is to greatly reduce the possibility of conductive debris being generated from repeated installation and removal of mating screws.”

Thread-locking torque performance is equivalent to applicable NASM25027 specifications.

Steel (PL) and stainless steel (PLC) versions install permanently in thin steel or aluminium sheets between l.0mm and 1.78mm thick. Shank lengths are .060” and 1.53mm.

Standard thread sizes are #4-40 to #10-32 and M3 to M5 – locking elements are black for metric versions and blue for US ‘unified’ threads.

Installation requires a press, during which locknut’s knurled collar embeds in the host sheet and displaces sheet material, which then fills the undercut cavity beneath the collar (see diagram) to captivate the fastener in the sheet.

“The strong knurled collar effectively receives the installation force and resists torque, exhibiting spin resistance greatly exceeding the torque exerted by the self-locking feature. Both the self-clinching shank of the locknut and the undercut contribute to high push-out values,” claimed Penn.

Penn Engineering makes products in the USA, Ireland and China.