Originally Posted by pug398
when we had "training" on adjusting timing belts for optical readers they gave us a little routine to follow. When you hold the drive pulley and rotate the driven pulley back and forth the top section of the belt will tighten and slacken. Measure the vertical height the belt travels while doing this and it should be no more than 1/32". Too tight and the belt wears prematurely as well as bushings. More slack and you lose the precision. After your final adjustment did it work out to be about this amount of slack? May be slightly different for this type setup.
I think that is a good way to check belt tension. I have tried different belt tension and the difference is not really that noticeable. You do not want belt tension that is either too loose or too tight. The 1/32" vertical height for the 120 groove belt we use seems very reasonable.
I have run the belt tension as loose as when I move the gimbal the tooth will skip to as tight as a drum where you can "twang" the belt.
You are right about the servo shaft cannot handle too much tension. That's why Servo City sells servo blocks to relieve the strain on the servo shaft.