Torque Value

[vsh]

How would one go about determining the torque value of a jam nut. It is 1"-12tpi. The application is a 1-12 threaded rod with a jam nut to lock it. It is under static load of about 12000lbs. Thanks for any info, VSH

 

[diamondjim]

VSH,
what strength rod are you talking about,
equivalent to grade 5 or grade 8.
If grade 5, you are looking at torque values of
640 ft-lbs dry or 480 ft-lbs lubed.
If grade 8, 1000 ft-lbs dry or 740 ft-lbs lubed.

 

[Ron]

I would not worry about a torque value for the jam nut. Use "turn of the nut" method, whereby you snug the jam nut, hold the main nut and turn the jam nut relative to the main nut by no more than 1/4 turn, since the "connection" at that point is not slip critical, and both mating faces are hardened.