Al wrote:

I bought a 6 X 12 Boyar Schultz Manual Surface grinder and mounted an
ENCO 1/2 x 7 wheel. The wheel had some bad vibration so I replaced the
spindle bearings. I have three Enco wheels and some vibrate more than
others, the wheels have the letters BAL painted on them so I expected
that indicated they were balanced. I was a Tool & Die Maker in the
late 50's and spent a significant amount of time using the 6 X 12
Boyar Schultz manual grinder. I never experienced a vibration and am
not sure where to begin sorting out this problem. The ENCO Wheels were
not very expensive and I wonder if the problem is the inexpensive
wheel or the drive mechanism.
Any suggestions are appreciated.
Thanks ....Al Basham

Is the spindle motor 3phase? Are you generating it with a static converter?

Wes