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The thread locking torque performance of Type PL and PLC PEMHEX® self-clinching fasteners is equivalent to applicable NASM25027 specifications. A nylon hexagonal element provides a reusable, non-metallic prevailing torque thread lock. The strong knurled collar receives the installation force and resists torque. The spin resistance of the knurl greatly exceeds the torque that can be exerted by the self-locking feature. As the knurled collar is embedded in the sheet, the undercut cavity beneath the collar is filled with displaced sheet material, thereby captivating the fastener in the sheet.

The color blue for fastener locking elements is a registered trademark. Unified fasteners have a blue nylon locking element and metric fasteners have a black nylon locking element.
Nylon insert, locking thread nuts – PL, PLC Metric
Nylon Insert Self-Locking Fasteners - Types PL and PLC 2
Unit of Measure
Items Nylon insert, locking thread nuts – PL, PLC Metric
PL-M3-ZI
Nylon Insert Self-Locking Fasteners - Types PL and PLC - Metric
Nylon insert, locking thread nuts – PL, PLC Metric
PL-M4-ZI
Nylon Insert Self-Locking Fasteners - Types PL and PLC - Metric
Nylon insert, locking thread nuts – PL, PLC Metric
PL-M5-ZI
Nylon Insert Self-Locking Fasteners - Types PL and PLC - Metric
Nylon insert, locking thread nuts – PL, PLC Metric
PL-M3-ZC
Nylon Insert Self-Locking Fasteners - Types PL and PLC - Metric
Nylon insert, locking thread nuts – PL, PLC Metric
PL-M4-ZC
Nylon Insert Self-Locking Fasteners - Types PL and PLC - Metric
Thread Size N/A M3 x 0.5 N/A M4 x 0.7 N/A M5 x 0.8 N/A M3 x 0.5 N/A M4 x 0.7
Thread Code N/A M3 N/A M4 N/A M5 N/A M3 N/A M4
Material Code N/A
A (Shank) Max. N/A 1.53 mm
Sheet Thickness1 N/A 1 to 1.78 mm
Hole Size in Sheet + 0.08 N/A 6 mm N/A 7.5 mm N/A 8 mm N/A 6 mm N/A 7.5 mm
C Max. N/A 5.98 mm a1363_1.jpg N/A 7.48 mm a1363_1.jpg N/A 7.98 mm a1363_1.jpg N/A 5.98 mm a1363_1.jpg N/A 7.48 mm a1363_1.jpg
D Max. N/A 5.52 mm N/A 7.01 mm N/A 7.52 mm N/A 5.52 mm N/A 7.01 mm
E Max. N/A 7.01 mm N/A 8.54 mm N/A 9 mm N/A 7.01 mm N/A 8.54 mm
T Max. N/A 3.56 mm N/A 4.20 mm N/A 4.45 mm N/A 3.56 mm N/A 4.20 mm
Min. Dist. Hole C/L to Edge2 N/A 4.32 mm N/A 5.59 mm N/A 6.35 mm N/A 4.32 mm N/A 5.59 mm
Max. Hole in Attached Parts N/A 3.50 mm N/A 4.50 mm N/A 5.50 mm N/A 3.50 mm N/A 4.50 mm
Fastener Materials - Locking Element N/A Black Nylon
For Use in Sheet Hardness3 N/A HRB 70 / HB 125 or Less
Thread Specification N/A Internal, ASME B1.13M, 6H
Fastener Material N/A Heat-Treated Carbon Steel
Standard Finish N/A Zinc plated per ASTM B633, SC1 (5µm), Type III, colorless N/A Zinc plated per ASTM B633, SC1 (5µm), Type III, colorless N/A Zinc plated per ASTM B633, SC1 (5µm), Type III, colorless N/A N/A
Optional Finish4 N/A N/A N/A N/A Zinc plated per ASTM B633, SC1 (5µm), Type II, yellow N/A Zinc plated per ASTM B633, SC1 (5µm), Type II, yellow
CAD Supplier N/A PennEngineering® (PEM®)
Inventory N/A {0} N/A {0} N/A {0} N/A {0} N/A {0}
  • 1 - Can be used in panel thickness of .040” to .060” / 1 mm to 1.53 mm provided the fastener is not fully installed. The knurled collar must be left protruding above the sheet to the degree that the sheet thickness is less than .060” / 1.53 mm.

    - K
  • 2 To minimize sheet distortion and maximize product performance, use a centerline-to-edge value greater or equal to the value specified.
  • 3 HRB - Hardness Rockwell “B” Scale. HB - Hardness Brinell.
  • 4 “BL” suffix will be added to part number to designate DuraBlack™ finish.