PennEngineering
PennEngineering
Corporate Headquarters – Danboro, PA
5190 Old Easton Rd.
Danboro, PA 18916
Phone: 215-766-8853
Toll-Free Phone: 1-800-237-4736 (U.S. only)
Email: info@pemnet.com
Website: www.pemnet.com
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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.
All metal, locking thread nuts – LK, LKA, LKS - Metric
PEMFLEX® Self-locking, Self-clinching Fasteners 2
Unit of Measure
1 

Part #

Thread Size x Pitch

A (Shank) Max.

Hole Size in Sheet + 0.08

C Max.

E Nom.

Fastener Material

Standard Finish

CAD

LK-M2.5-1MD N/A M2.5 x 0.45 N/A 0.97 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M2.5-2MD N/A M2.5 x 0.45 N/A 1.38 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M3-1MD N/A M3 x 0.5 N/A 0.97 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M3-2MD N/A M3 x 0.5 N/A 1.38 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M4-1MD N/A M4 x 0.7 N/A 0.97 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M4-2MD N/A M4 x 0.7 N/A 1.38 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M5-1MD N/A M5 x 0.8 N/A 0.97 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LK-M5-2MD N/A M5 x 0.8 N/A 1.38 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A Carbon Steel N/A Black, Dry-film Lubricant over Zinc Phosphate N/A CAD Icon (for items table)
LKS-M2.5-1MD N/A M2.5 x 0.45 N/A 0.97 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M2.5-2MD N/A M2.5 x 0.45 N/A 1.38 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M3-1MD N/A M3 x 0.5 N/A 0.97 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M3-2MD N/A M3 x 0.5 N/A 1.38 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M4-1MD N/A M4 x 0.7 N/A 0.97 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M4-2MD N/A M4 x 0.7 N/A 1.38 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M5-1MD N/A M5 x 0.8 N/A 0.97 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKS-M5-2MD N/A M5 x 0.8 N/A 1.38 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A 300 Series Stainless Steel N/A Black, Dry-film Lubricant N/A CAD Icon (for items table)
LKA-M2.5-1 N/A M2.5 x 0.45 N/A 0.97 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M2.5-2 N/A M2.5 x 0.45 N/A 1.38 mm N/A 4.37 mm N/A 4.35 mm N/A 6.35 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M3-1 N/A M3 x 0.5 N/A 0.97 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M3-2 N/A M3 x 0.5 N/A 1.38 mm N/A 4.75 mm N/A 4.73 mm N/A 6.35 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M4-1 N/A M4 x 0.7 N/A 0.97 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M4-2 N/A M4 x 0.7 N/A 1.38 mm N/A 6.76 mm N/A 6.73 mm N/A 8.73 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M5-1 N/A M5 x 0.8 N/A 0.97 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
LKA-M5-2 N/A M5 x 0.8 N/A 1.38 mm N/A 7.92 mm N/A 7.9 mm N/A 9.53 mm N/A 7075-T6 Aluminum N/A Plain N/A CAD Icon (for items table)
Unit of Measure
1