First, The headstock housing is aluminum so normal tightening is all that is needed as overtightening will strip screw threads or break something. I have to use steel inserts where someone thought more is better.
The last eccentric bushing I ordered was the latest one that I know about. There has been many different versions of the eccentric bushing. Over tightening the set screw can be felt and sometimes heared when turning the idler shaft. If your headstock is only getting fairly warm after operating for a time, I do not believe there is anything wrong with it. I find listening and feeling the headstock as you change speed can help determine any unusal noises/sounds/vibrations. The clamp bolt will only cause problems if you are using a split eccentric bushing. If it is a solid bushing, then the most that can happen is breaking an ear off the housing when over tightening.
All my Shopsmith headstocks gets hot after hard use. As long as I can hold my finger on the housing for a couple seconds, I don't worry about it. If it feels like you will get burned when you touch the housing, then it is too hot and needs to be checked. With no load when operating for a while, then the housing will get fairly warm at HIGH speed. It should not be hot. I find that belt tension and alignment (a problem on Gilmer drives) also can cause heat problems.
The screw and washer above the eccentric bushing is a safety device to me. I use a larger body washer so the eccentric bushing or the idler shaft can not come out that way when operating if the set screw or clamp bolt vibrates loose. I just use a regular phillips screwdrive to tighten the screw until the washer is againest the housing.
eldyfig wroteAbout the eccentric bushing:
Bill (or anyone who knows), is the solid bushing that you mention above, is it what SS ships if I were to order one now? Is it the new version?
I think I may be running into exactly what your customer may have had. My aux. spindles are warm. Never noticed it too much in saw mode. But, since it has been it drill press mode, I have definitely noticed the heat. I am figuring that when I saw, I make my cut and turn the SS back off, it cools off. However, in drill press mode, the SS runs longer since I am drilling multiple holes. Heat keeps building. It got to the point where the upper spindle was warm, the lower spindle was warmer, and the headstock itself was actually getting warm I don't think the clamp bolt is too tight. It could be possible the bushing setscrew is. I am about to go check it out. The headstock is open right now. I just did maintenance on it two months ago. I have been known to over tighten things.
What about the screw and washer above the bushing (at the 12 o'clock position)?. It looks like it holds the bushing in. What is the deal on it? Can that be too tight?