[Winnfield]

The inside is just pitted from use. the spindle itself on the outside is 0.0005

The way you measured that can't possibly tell you anything about your spindle. You could simply be measuring the runout of your collet, etc.

If your spindle is damaged on the taper, keeping you from indicating from that surface, what makes you think that the problem has to do with the bearings at all?

[Winnfield]

and whatever that music is you are listening to might be your problem, as well.

[nateman_doo]

The way you measured that can't possibly tell you anything about your spindle. You could simply be measuring the runout of your collet, etc.

If your spindle is damaged on the taper, keeping you from indicating from that surface, what makes you think that the problem has to do with the bearings at all?

The bearings sounded like they were starting to screech. The inner taper is a bit banged up from installing collets in and out all the time for close to 2 years.

I took lots of pictures of the process, just waiting for a free moment to write it all up.

[SCzEngrgGroup]

The bearings sounded like they were starting to screech. The inner taper is a bit banged up from installing collets in and out all the time for close to 2 years.

I took lots of pictures of the process, just waiting for a free moment to write it all up.

The taper should never get "banged up", no matter how long you've been using it! If it does, your runout will go out the window. You should never stick anything in the taper that isn't perfectly clean, specifically so it doesn't get "banged up".

Regards,
Ray L.

[dertsap]

have you checked the run out when there's a tool in the spindle ?
If its bad then there are a few ways to fix it

[nateman_doo]

A new spindly isn't that expensive from LMS. If I cared that much (or it was that inaccurate) I would certainly look into replacing it. It only took me an evening to yank out the spindle and replace the bearings. Pics to follow.

[nateman_doo]

THE REMOVAL PROCESS


Step one requires you to remove the spindle locking nut.

Pretty self explanatory at this point.

Next thing I did was taking a 2 foot long 1/2" threaded rod down the spindle.

I had a set of 2x4x6, and 1x2x3 blocks to help. I put a nut at the bottom and using the 123 blocks as spacers and the 246 block to span the gap. I put a not on top of the spindle and cranked it down which brought out the spindle and lower bearing in one shot.

Almost out:


Here is the newly freed spindle.


Here is how I got the top bearing out.

I used some 1.25 pvc pipe (i forget OD/ID) and used the 123 blocks again as a spacer and this time used part of my 1/2" clamping kit to bridge the gap. The PVC held up quiet well.

Installing the top bearing.

I took some 2x2 tubular steel to press the bearing into place. Then after I stopped getting lazy I turned some scrap aluminum to make something that only pressed on the outer race of the bearing. The 246 block acts as the base which when tightening the nut, draws either the block up, or the bearing down. Block beats bearing, so it seats nicely.

[nateman_doo]

Here is the removal of the lower bearing still on the spindle.

the same rod was threaded completely through, and the 246 was clamped in a shop vise. The extra clamping blocks were needed to give more space to "pull the spindle down" through the old bearing.

Installation:

There is the aforementioned part I turned when I stopped being lazy. This presses only the inner ring down, without any lateral stress on the outer race.

Now for the final step:

The spindle and lower bearing are inserted from the bottom. Then the entire assembly is drawn in from the bottom up. the 246 block was primarily used all the time because it already had a hole to fit the 1/2" threaded rod. So much for not being lazy

Then put the spindle nut back on.

Hope this helps anyone.

[mchabot]

I have made modification on my X2 to use tapered roller bearing instead of standard depp groove bearing (morse taper spindle, 30206 bearings)

What you must do:

Polish the upper bearing race to have a slip fit instead of shrink fit, this way the bearing preloading is possible (even for deep groove).

Put the spindle into freezer, inner bearing cage+roller at 60/70C degrees, now it should fall into place without any pressure.
Put head casting into owen, again 60/70C degrees. Now the outer cages also fall into place nicely.
You can then mount spindle+upper bearing without any stress.
Note that you should add bearing shield (mine are in ptfe) to avoid any contamination, and that you need reducing the pulley size as taper bearings are wider.

[nateman_doo]

Do you have some part numbers?

[mchabot]

Bearings are unamed 30206 bearings, I have some timken in stock but never mounted them.

Other part (shields) are custom made in aluminum with a teflon ring to provide little sealing (without drag).

Note that taper roller cannot go fast, 3000rpm is ok, 4000rpm probably the limit.
Angular contact bearing can go higher, but are really tricker to mount, and cannot be unmounted wihtout destroying the bearings.

I have attached pics of the mounting: lower bearing press fit (on inner race), top bearing cup fitted then with the spindle in place. Sorry no pics of the seals as I have made them later.
Upper bearing inner race is almost slip fit after polishing the spindle on the lathe with fine sandpaper+oil. No degradation in spindle runout seen.

[nateman_doo]

wow, that looks pretty sweet. is that number for the top, or bottom bearing?

[mchabot]

MT3 spindle has the same bearing size on top and bottom (30x62). For R8 you will need different bearing on the bottom, 32007 I guess (35x62x18).

[nateman_doo]

ahh, makes sense.

[MiniSoCalCNC]

Yeah, you should at least get deep groove ball bearings not general purpose, angular contacts would be even better.
The lower bearing on the X2 is the same size as on the g0704, you can get cheap AC's at VXB good for 9500 rpm at vxb.
7007B Angular Contact Bearing 35x62x14 Ball Bearings
they have better Japanese Nachi bearings too like this one for the upper.
7206 Nachi Angular Contact Bearing 30x62x16 Steel Cage C3 Japan Ball Bearings
I'm using some decent AC bearings from Bearings Direct that are good to 16000 rpm.
7007C Bearing
7206C Bearing
get the good Kluber grease and you can run as hard as the X2 could possibly stand.
G0704 Belt Drive
Hoss

I know this is an ancient thread but - thanks to Hoss - I just pulled trigger on bearings from VBX to hopefully aid in my spindle motor upgrade ...