PEM® S-RT™ free-running locknuts are free-running until clamp load is induced. A modified thread angle on the loaded flank provides the vibration resistant locking feature.
  • Screw turns freely until a clamp load is applied.
  • Resistant to vibrational loosening.
  • Back side of panel is flush or sub-flush for screw installation.
  • Locking feature reusability is not affected by number of on/off cycles.
  • Uses same mounting hole and installation tooling as standard S™ nut fasteners found in PEM® Bulletin CL.
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Unit of Measure

Thread Size x Pitch

 N/A M8 x 1.25

Thread Code

 N/A RTM8

Shank Code

 N/A 2

A (Shank) Max.

 N/A 2.21 mm RT-Drawing.jpg
Rec. Min. Sheet Thickness1 N/A 2.29 mm

Hole Size in Sheet + 0.08

 N/A 10.49 mm

C Max.

 N/A 10.47 mm

E ± 0.25

 N/A 12.70 mm

T ± 0.25

 N/A 5.84 mm

Min. Dist. Hole C/L to Edge

 N/A 9.65 mm

For Use in Sheet Hardness

 N/A HRB 80 / HB 150 or Less

Thread Specification

 N/A Modified thread form on loaded flank. Will accept a maximum material 6g screw.

Fastener Material

 N/A Hardened Carbon Steel

Standard Finish

 N/A Zinc plated per ASTM B633, SC1 (5µm), Type III, colorless

CAD Supplier

 N/A PennEngineering® (PEM®)
  • 1 For maximum performance, we recommend that you use the maximum shank length for your sheet thickness.