Doozer, it is a 612. I saw your older post about how you redid your machine, yep another question. You said you went through your spindle explaining that it wasn't that difficult. One of the posts I read on the original post, this guy went on about how the average Joe can't do it how at one place he worked the failure rate of spindles was about 80 or 90 percent. I find this hard to believe, if your clean and careful shouldn't be a big deal. Did you notice the high spot marks he was refering to on yours, and is there anyway to tell what type of bearings it might have from the outside? Any direction would be greatly appreciated. Any chance of just repacking the old bearings if they still look good?
I assume you mean the Boyar Shulyz 612. Is yours direct drive or belt drive? Stay with 3 phase, single phase motor is BAD on a grinder. The vabrations ruin the finish. Go to automationdirect.com and get a GS1 VFD. They even have 120v in, 230v ac 3 ph out. And for $129 it is cheap. Variable speed wheel is nice also. A faster wheel acts harder and finer. A slower speed wheel acts softer and more fraible. This site had a manual under the manuals section or check on 3-phase light bulb's site. Can't check my ser no right now, it's still buried from my move.