I have been chasing noise on my lathe, and have been pretty successful. As I have reduced the noise on the lathe I noticed that there was play on my right idler causing noise, and investigating I noticed that the bolt is obviously not original. The head of this bolt is too small to properly secure the pulley bearings. It is also possible that the chamfer on the id of my replacement MRC bearings is different than the original New Departures, so the bolt used to be good, but is not now. In any event, what do you call this kind of thin head bolt? I cannot find anything with a large enough head on McMaster, etc.
