Locking and Non-locking Threads
These fasteners provide load-bearing threads in thin sheets and permit up to .030” adjustment for mating hole misalignment.

The self-clinching feature offers fast and simple assembly. The fasteners are squeezed into prepared holes using any standard press. The sheet remains flush on one side, and the fastener is permanently locked in place.

Extra strength and support in assembly is obtained by the threads of the floating nut extending fully into the retainer shank (a unique PEM feature). A self-locking version of the fastener is also offered. Thread locking torque performance is equivalent to applicable NASM25027 specifications.

Non-locking Type A4 and self-locking Type LA4 fasteners provide load-bearing threads in stainless steel sheets as thin as .038” with hardness up to HRB 88 on the Rockwell “B” scale.

Many PEM Type AS and AC self-clinching floating fasteners correspond to sizes in US NASM45938/11 specifications. Check our web site for a complete Military Specification and National Aerospace Standards Reference Guide (Bulletin NASM).
Unit of Measure

Thread Size

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

Thread Type

N/A Self-Locking a1369.jpg

Thread Code

N/A 440

Shank Code

N/A 1

A (Shank) Max.

N/A .038 in a1368.jpg

Min. Sheet Thickness

N/A .038 in

Hole Size in Sheet + .003 - .000

N/A .290 in

C Max.

N/A .289 in

D Max.

N/A .290 in

E ± .015

N/A .360 in

T1 Max.

N/A .130 in

T2 Max.

N/A .190 in

Min. Dist. Hole C/L to Edge

N/A .300 in

Float

N/A .015” minimum, in all directions from center, .030” total

Fastener Material

N/A 400 Series Stainless

Fastener Materials - Retainer

N/A 400 Series Stainless Steel

Fastener Materials - Nut

N/A 300 Series Stainless Steel

Retainer Finish

N/A Passivated and/or tested per ASTM A380

Nut Finish

N/A Black Dry-film Lubricant
For Use in Sheet Hardness1 N/A HRB 88 / HB 183 or Less

Thread Specification

N/A Internal, ANSI B1.1, 2B

CAD Supplier

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