ORIGINAL: Ernie Misner
Best thing I ever did was get a 1/4x32 die for cleaning up new plugs before installing. Apparently the plug's threads are just rolled and not precision cut from the factory. You would be amazed at all the shaving that come off of new plugs to make them right.
Ernie Misner
I have a Higley 1/4-32 tap but no die. The tap cost me $7. I haven't had any problems stripping threads with my McCoy plugs. Though your comment does inspire me to get a 1/4-32 die just to have one. My hobby shop has a Higley die for $14