Miniature Self-Clinching Fasteners – Types U, UL, FE, FEO, FEOX, FEX


Miniature Self-Clinching Fasteners – Types U, UL, FE, FEO, FEOX, FEX

PEM® brand miniature fasteners fit into a minimal space and provide strong, reusable threads.

Types FE, FEO and UL are self-locking. Types FE and FEO thread locking torque performance is equivalent to applicable NASM25027 specifications. Type UL self-locking nuts meet locking torque requirements specified herein. Some sizes of FE, FEO, and UL can be ordered to NASM45938/7 specifications. Types FEX, FEOX and U have free-running class 2B/6H threads.

PEM miniature fasteners provide immediate visual indication when proper installation has been accomplished.

A strong, knurled collar, which is completely embedded in the sheet, guarantees against rotation of the fastener in the sheet. The torque-out resistance of the knurl greatly exceeds the torque that can be exerted by the selflocking feature.

When this collar is embedded in the sheet, the undercut cavity beneath the collar is filled with displaced sheet material thereby developing pushout resistance.

A dry-film lubricant applied to these fasteners provides the smooth, non-galling prevailing torque performance necessary for reliable locking and for reusability.


Thread Code
Thread Size
.138-32 (#6-32)
Thread Specification
Internal, MIL-S-8879, UNJ-3B
Fastener Material
300 Series Stainless Steel
Standard Finish
Black, Dry-film Lubricant
For Use in Sheet Hardness
HRB 70 / HB 125 or Less
Product Category
Miniature Self-Clinching Fasteners – Types U, UL, FE, FEO, FEOX, FEX
CAD Supplier
PennEngineering® (PEM®)
Thread Type
Application Type
Automotive Electronics, Consumer Electronics, Datacom, Telecom
Base Panel Material
Aluminum, Steel
Fastener Characteristics
Locking, Miniature, Threaded Internal
Automotive Electronics, Consumer Electronics, Datacom & Telecom
Installation Equipment/Method
C-Frame Automatic Feed, C-Frame Manual Feed
Product Type
Technology Type
A Shank Max
C + .000 – .005_in
E ± .005_in
Hole Size in Sheet + .003 – .000_in
Max. Hole in Attached Parts_in
Min. Dist. Hole C/L to Edge_in
D Max._in
Sheet Thickness_in
.059 to .070in
T + .015 -.000_in


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