[Amps] Stuck Setscrews

[Rick]

Good morning Vic,

First suggestion is that if the wrenches are turning to no effect you 
have the wrong size (SAE vs. Metric). This is easy to correct.

Second suggestion is you stripped the setscrews ... not so good, but 
still workable.

If you have stripped the setscrews, take the proper sized hex wrench, 
dip the end in water, and then roll it in some dry scrubbing powder 
(Ajax, Comet, etc). Then firmly apply pressure while turning. BTW, this 
works on stripped Phillips head screws as well. Just remember to discard 
the removed screws and clean your hex wrench.

If you find you were using the wrong size hex wrench, and you can't turn 
anything, heat the business end of the hex wrench (100°C or so) ... you 
may want to use pliers to hold the wrench. When hot, insert the hex 
wrench into the setscrew and let it sit for about 30 seconds. This will 
heat the locking compound sufficiently to help break it free. Then, 
loosen. Repeat as necessary.

If the threadlock used was Loktite Red, it will take localized heat 
greater than 550°F (287.778°C).


For reference: "Most thread-locking formulas are methacrylate 
<https://en.wikipedia.org/wiki/Methacrylate>-based and rely on the 
electrochemical activity of a metal substrate to cause polymerization 
<https://en.wikipedia.org/wiki/Polymerization> of the fluid. 
Thread-locking fluid is thixotropic 
<https://en.wikipedia.org/wiki/Thixotropic>, which allows it to flow 
well over time, yet still resist shocks and vibrations. It can be 
permanent or removable; in the latter case, it can be removed with heat, 
for example. Typically, brands are color-coded to indicate strength and 
whether they can be removed."

Hope this helps.

73,

Rick

NM3G

Vic wrote (in part)

... but I can't budge the setscrews holding the old one. Allen wrenches 
twist to no effect.