I'm fairly certain that the only thing tensioning the motor belt when running is the spring on the end of the motor shaft (conventional headstock only). When you change speed, moving the control sheave, it either increases or decreases the tension and the floating sheave moves in response to balance the tension. The motor belt always seems to have low tension because if you press on it you will compress the spring. There is no procedure in the manual for tensioning or checking motor belt tension on the conventional headstock that I've ever seen. The eccentric adjustment is only for the upper belt tension.RFGuy wrote: ↑Tue Nov 02, 2021 4:40 pm ...I believe the poly V was tensioned at like 1/8" deflection when pushed with a finger and the "motor" belt was well over 1/2" deflection (hence the slip). Correct me if I am wrong, but isn't the rule of thumb to tension the "motor" belt to no more than 1/4" deflection? So, I went about adjusting the "motor" belt until I got to 1/4" deflection but at this point the poly V deflection was I don't know how much. Let's just say it was tight, much tighter than 1/8" deflection at that point. I finished my cuts without binding and ordered new belts. Even with new belts after this, what I have noticed is that my Mark V always has much larger deflection on the "motor" belt than on the poly V belt. The problem, as I see it, is there is no independent way to adjust belt tension on the poly V belt relative to the "motor" belt. Is all this normal, or is it possible that something is wrong with my Mark V since I can't get what the expected tension is on both belts with the eccentric adjustment alone?
It's different in the PowerPro. Both belts are under tension. So turning the eccentric will tighten one belt while loosening the other.
- David