On Aug 16, 8:55*am, Joseph Gwinn wrote:
This is a continuation of the thread "Millrite MVI spindle bearings may need
replacement" first posted on 31 July 2010.

I now have the spindle out of the quill and the taper roller bearings off the
quill. *I made (from a cast iron pipe fitting) a special pusher to avoid
crushing the grease slinger, and (lacking a press) used a piece of 1/2-13
allthread passed through the drawbar hole to generate the needed force. *
Greasing the spindle just ahead of the sliding bearing race also helped.

The taper roller bearings are not in that bad condition, given that the grease
had turned into some kind of chalky cake. *However, the absence of grease had
allowed coolant to enter and corrode the bearing "cup" (the outer race) of the
lower bearing assembly in a few places. *I assume that the area weakened by
corrosion will soon fail. *The rollers are not yet clean enough to tell if they
have been compromised, but one assumes that there has been damage.

It is not obvious how one would grease these bearings without removing spindle
from quill (which isn't that hard, but still). *I have heard of people instead
using DTE24 or heavier hydraulic oil fed in through the plug in the side of the
quill, and letting it drip out of the bottom of the quill. *This may be a better
approach. *What experience do people have with this?

For the record, the two outer races ("cups") are each Timken 19268; and thetwo *
assemblies of inner races ("cones"), rollers, and cages are each Timken 19150. *
The stated ID of a 19150 cone is 1.5000". *

The quill shaft is about 0.0011" larger than the stated cone ID, so it was a
light press fit. As others have noted , this cripples the running preload
adjustment by turning a ring nut on the spindle, and press fits are too hard to
get exactly correct. *

Is there a standard solution? *I'm tempted to polish the spindle shaft down
until the (new?) bearings are a (hand) push fit. *Has anyone done this?

Joe Gwinn

There are people probably a lot more knowledgeable on this subject,
but here’s my two cents. When you’re pressing the bearing into place,
you’re putting the load on the outer race. When you tighten the ring
nut, it preloads the inner race and rollers. The force used getting
the bearing set in the bottom of bushing shouldn’t come into play.
(If the bushing was too tight, I suppose that you might crack the
bushing or outer bearing race.)

I’ve put in a grease-fitting in the rod end of an old Keller power
hacksaw that I’ve refurbished and it seems to have worked well. I
think that my repair will make it last much longer, but what you
probably have to guess is the level of stresses in the area supporting
the bearing. If you drill there to put an oil cup or grease fitting,
you could possibly cause a stress riser. If the bearing support is
low-stressed, you’re probably safe to drill & tap it to add a
lubrication fitting.