Type CLA aluminum nuts are recommended for use in aluminum sheet with a hardness of HRB 50 or less on the Rockwell “B” scale.

Unplated threads are sized to accept a basic go gauge after .00025” plating.
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Unit of Measure

Thread Size

 .250-20 (1/4-20)

Thread Code

 0420

Shank Code

 3

A (Shank) Max.

 .120 in
CLA-Dwg.jpg
Min. Sheet Thickness1 .125 in

Hole Size in Sheet + .003 - .000

 .344 in

C Max.

 .343 in

E ± .010

 .440 in

T ± .010

 .170 in
Min. Dist. Hole C/L to Edge2 .34 in
For Use in Sheet Hardness3 HRB 50 / HB 82 or less

Thread Specification

 Internal, ASME B1.1, 2B

Fastener Material

 Aluminum

Standard Finish

 None

CAD Supplier

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