PEM® PEMFLEX® self-locking, self-clinching fasteners retain their repeated use and effective prevailing locking torque.
  • Shoulder provides increased performance.
  • Flexing action permits repeated use and effective locking torque.
  • Flange provides positive stop during installation.
The thread locking performance of Types LK, LKA, and LKS PEMHEX self-clinching fasteners (with MD finish) is equivalent to applicable NASM25027 specifications. The self-clinching feature is the same tried and proven design preferred and appreciated for fast, simple assembly. These fasteners do not protrude through the reverse side of the sheet and provide positive, permanent attachment with high torque-out (many times greater than locking torque) and pushout resistances.

PEM all-metal, self-locking fasteners are available in steel, stainless steel, and aluminum. Types LK (steel) and LKS (stainless) are treated with a black dry film lubricant for better locking performance. Type LKA (aluminum) must be used with a lubricated screw. The PEM design utilizes two rugged, semicircular flexing jaws instead of several less-supported segments. The greater ruggedness and retention of this PEMFLEX action prevents relaxation and loosening of the fastener in severe service.

This PEMFLEX design also protects the screw threads. Clearances obtained by only two interruptions of a full circumference, together with the spreading of the jaws by the entering screw, minimize the possibility of thread damage.
Unit of Measure

Thread Size

N/A .112-40 (#4-40)

A (Shank) Max.

N/A .054 in a1093.jpg

Min. Sheet Thickness

N/A .056 in

Hole Size in Sheet + .003 - .000

N/A .187 in

C Max.

N/A .186 in

D Max.

N/A .185 in

E Nom.

N/A .250 in

T ± .010

N/A .135 in

Min. Dist. Hole C/L to Edge

N/A .156 in
For Use in Sheet Hardness1 N/A HRB 70 / HB 125 or Less

Thread Specification

N/A Internal, ANSI B1.1, 3B

Fastener Material

N/A Carbon Steel

Standard Finish

N/A Black, Dry-film Lubricant over Zinc Phosphate

Anvil Dia.

N/A .500 in

Anvil Depth

N/A .218 in

Breaker Corner

N/A .005 in

Punch Dia.

N/A .500 in

CAD Supplier

N/A PennEngineering® (PEM®)
  • 1 HRB - Hardness Rockwell “B” Scale. HB - Hardness Brinell.