Installation Torque Specs These torque specs apply to the steel t-nut hardware kits available with our fixture plates. Bolt Size Torque 1/2" & M12 60 ft-lbs [81 N-m] 3/8" & M10 21 in-lbs [28.5 N-m] 5/16" & M8 13 ft-lbs [17.5 N-m] For other hardware sizes or materials, this NASA document is a fantastic reference for various materials, thread sizes, and thread engagement lengths. Fixturing Hole Torque Specs Appropriate bolt torque for workholding depends on a variety of factors, but the most important to consider is the thread engagement of the stud or screw into the fixture plate. Keep in mind that our 1/2" and M12 fixture plates have a 1/4" [6.35mm] deep counterbore at the top of each thread which reduces thread engagement by that depth. Torque specs are given by engagement length (e.g. 0.5x⌀ on a 1/2" [12mm] bolt is 1/4" [6mm] of thread engagement). A good rule of thumb is to always have at least three full threads (3x the thread pitch) engaged. Plate Material Thread Size 0.5x⌀ Engagement 1.0x⌀ Engagement Steel 1/2" & M12 34 ft-lbs [46 N-m] 50 ft-lbs [68 N-m] Aluminum 1/2" & M12 18 ft-lbs [24.5 N-m] 45 ft-lbs [61 N-m] Aluminum 1/4" & M6 not recommended 75 in-lbs [8.5 N-m]
