Tim Wescott wrote:

The bearings are TIGHT on the spindle, to the point that tightening the
nut won't pull the bearings together.

Now this is stupid. One bearing has to be tight (OK, not necessarily
with tapered) and the other one has to have a interference fit. Best, if
you just can move it with the hand.

So, I would buy new bearings, see how they fit and hone one seat to make
a snug fit. Shrink (heat and freezer) the other bearing on. I've done
that on my lathe. There were only some 1/1000mm to be removed. I did it
with sanding strips (the ones you get on coils, about 15mm wide) and
oil. 10 strokes, rotate, 10 strokes, rotate, ...

Note, that you get bearings in different tolerance classes. P7 (or P6?)
is for precision machines. But it might be wasted money for your's :-))


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de