We are using a locking patch on 4-40 stainless screws. The patch is applied by the supplier and has a prevailing torque as high as 5 in-lbs. I find that rather high for a 4-40 screws. We have had some situations where we would engage a few clean threads, hit the patch and strip the threads on the end of the screw because the torque required to pierce the locking patch is too high.
Question is: what is a typical prevailing torque value for locking mechanism on 4-40 screws? I'm thinking of specifying MIN=1 in-lbs, MAX=2.5 in-lbs
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