View Full Version : changing spindle bearings (help!!)

06-12-2005, 10:49 AM
I have been looking into changing the bearings in the quill of my Wells Index model 745 mill. (they need to be changed!)

I can send it to Wells Index and they will do the job for $350.00 USD, which is I believe a good value.

Except... I live in Canada.
Just about any way you slice, dice or scheme that job is going to cost me $700.00 cdn. Exchange, tax, shipping and brokerage usually converts any $$USD price into double. (sucks don't it?)

I can buy a set of the correct bearings locally for about $400.00 cdn, and being a competent mechanic I don't think that it "should" too difficult a job to do.

Has anyone done this? Are there any big "watch outs?"

Any and all advise considered and appreciated.



Ed Miles
06-12-2005, 11:35 AM
Pete, you do not have to send it to the US for repair. Let's try an Email approach. Do you have a drawing for this spindle. And the correct bearing numbers that are in the spindle. If you can FAX a copy of a drawing I may be able to help out. I am just south of you in Stratford and we rebuild any and all types of milling,turning and grinder spindles. Do you know if there is any housing bore wear or shaft seat wear.

Ceramics mean speed

06-12-2005, 11:43 AM
Damn Pete. I don't know for sure, but the worst of it is that may be a one-way situation. Would someone from here experience similar gouging if we sent something to Canada to be serviced?

For a few hundred bucks it would be worth taking a vacation across the border and get the spindle re-done while you're at it. They could even inspect the spindle as you cross both ways and customs would notice no difference (I don't see the border patrol noticing the smoother spindle on the return trip).

Not having replaced precision bearings before, I have no other suggestions other than looking for a witness mark on the new bearings and aligning the corresponding marks when you install them, which you probably already knew.

Good luck.

06-12-2005, 05:45 PM
Ed please send me an email address


Ed Miles
06-12-2005, 05:55 PM
Pete, my Email address is listed in the profile box.

Regards Ed Miles

06-12-2005, 07:53 PM
Check your email


06-20-2005, 09:30 PM
Hello again:
Still fiddling around with the spindle bearing on my Wells Index mill.
As I indicated previously, they seemed to be noisier than I thought correct and had no apparent preload.

So, in anticipation of changing them I made a couple of the special tools needed and generally tried to find my way around this thing.

I have previously spoken to Rick at Wells-Index about the proceedures for changing these bearings, and one thing he told me was that the bearing retaining nut in the spindle should be "quite tight"
I checked this tonight and found that I could tighten it at least 1/2 a turn, and when I did, I increased the preload (obviously) and the bearings now are a great deal quieter.

Could it be that the bearings weren't tight enough, and this made them noisy?

Is there a chance that I have made thing better in the short term but worse in the long run?

What is the collective opinion on removing these bearings,re-lubing them and reinstalling them.
Would it be worth the effort?


06-20-2005, 10:53 PM
What is the collective opinion on removing these bearings,re-lubing them and reinstalling them.
Would it be worth the effort?


part of being a machinist is working on spindles, if you own a mill you might as well get to know it inside and out.

I say go for it.

If you take it out take a picture.

good luck.

06-20-2005, 11:08 PM
You can remove the bearings wash them and inspect them. If you see pitting or the bearing surface looks like a matt finish (not polished) then it is possible the bearing is breaking down. Never spin a dry bearing with an air compressor! You can slowly turn the bearing while pressing down on it to see if you can feel any roughness.
It might be that the bearing is noisy because it has to much end play or not enough lube. Low lube is a bad problem as it can consume bearings quite fast.
To have to little end play is just as bad if not worse, then to much.
Set your end play AFTER the bearing has run and is warmed up. Leave a little more end play then you think is right and check the spindle TIR to see if it is within specs. If it is leave it alone. It's most likely adjusted correctly. If it's still noisy you might have bad bearings. You can do this test before you disasemble the spindle to save all the work and time of a possibly needless job.

06-20-2005, 11:13 PM
When I make a precision spindle I completely build it then machine and grind the taper by turning it in the lathe. This way I get the best accuracy possible. I did this on a watch making lathe and got it under a tenth.(.0001)