Hi,
Noticed this old thread, and jumped in to say I am finishing up a complete teardown & restoration of a Rusnok 850. I have had the spindle out and have confirmed the bearing numbers both by talking to EM and double checking against my machine. I cannot say whether they are identical for your model 70, but there is a good likelihood that they are.
The upper spindle bearing is a standard WC87503.
The lower spindle bearing is a 5204zz double shielded pre-loaded double row bearing
Both are just ABEC 1. You can get the pair for around $50 from a good MFG (a bit more if you want SKF)
Getting the spindle and bearings out is pretty easy -- you'll just need a flat pin spanner wrench with 1.5" pin distance to undo the spanner nuts at the bottom/underside of the head casting where the spindle comes out and also a 3/4"-2" hook spanner to undo the spline nut that holds the bearings onto the spindle. You probably don't have either tool, but they're cheap or you can make them. All of the nuts to do this are standard (not reverse) direction thread. Obviously, you'll need a press to get the old bearings off/new ones on. Oh, and you may need to undo the uppermost of the 3 bolts that holds the quill downfeed handle onto the quill, as if it pokes through the quill even a little bit it will block the spindle from sliding down/out.
I have done a full writeup on how to do the spindle bearings for myself, and I can share it with you if you PM me.
OH -- one more thing -- are you SURE that it's the spindle bearings causing vibration? There are also two drive bearings (separate from spindle bearings) under the spindle pulley. They are just 6005 bearings -- very standard. Replacing these takes a few more minutes of disassembly compared to the spindle bearings as you have to pull the spindle pulley off, get the main alu. casting off with it, and some other stuff. It's all still pretty easy unless like mine yours are stuck from old grease, in which case it takes some time and kroil.