SDS speed control

If your belt is slipping significantly; no amount of correction from the SDS will help.

I would think something that severe would be immediately audible....

Shakey

How does the table sound? If the table sounds alright, then perhaps you are using the strobe disc and light incorrectly. What are you using as a light source and strobe disc?

if your wooden/plastic motor spindle the belt touches is the wrong diameter the sds will be adjusted to a level it is not designed for and never settle down. this happened to me. vpi sent me a smaller diameter and cured problem

Thanks for all the advise/tips. I just got in the mail today a Keystrobe disc and associated Keystrobe Quartz strobe light. Will try it out when home from work. It all sounds good but I want to insure accurate speed with a proper strobe set up. Thanks again.

Shakey- Belt slippage doesn't have to be, "severe" to show with a strobe/disc and not everyone can discern minor speed/pitch variations aurally. The OP did say, "a slow spin to the right."