G0704 Spindle bearing upgrade - Vertical play/slop on spindle shaft.

[Signal9]

I upgraded the G0704 spindle bearings and watched 3 different G0704 videos. Hoss, RussStuff, & Franco.

My question is that after i assembled installed the new bearings and shims, I noticed I have a slight vertical slop.

If I hold the spindle housing with one hand and grasp the spindle shaft, I can move the shaft up and down a small amount.

I used the following:

Bearings from VBX.com

8891 (7007B)
8889 (7005B)

And the following shims.

McMaster-Carr
98055A346 (35x45x1 Shim) 4 shims
98089A404 (25x36x1 Shim) 3 shims

The upper and lower bearing dust covers are snug, after finger tight, i gave it another 1/8 snug/twist.

Any thoughts?

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[coherent]

Does the spindle shaft move inside the quill or does the quill move. If it's the entire quill, did you reinstall the quill locking lever and brass pin? If it's the spindle, most likely the adjuster nut is not tight enough. If you didn't have or make a tool to use that fits the pin holes properly to aid in removal/installation of the nut and are just tapping it around with a screwdriver or something else, it's hard to thread/ tighten properly. Mine seemed tight until I used the right tool... then it turned another rotation or two before really seating properly.
The only other possibility I can think of is that the specs on these parts and machining aren't necessarily exactly the same over the years or every machine and measurements may differ and you may need another shim?

[Signal9]

Hello,

I did use a pin spanner tool to remove and reinstall the upper and lower spindle dust covers.

I will press it apart today and see if adding shims corrects it.

thanks

[Signal9]

Success!

For the top bearing, I used 6 shims instead of 3.

For the lower bearing I use 5 shims instead of 4.

The spindle shaft has a very very small amount of vertical play when outside the quill assembly. I figure HEAT/expansion will cause it tighten on itself from within and so I did not tighten the upper bearing dust cover cap any further.

when placed back into the milling head, the vertical play is all gone.



I probably didn't need the 5th shim on the lower bearing, but wasn't going to press everything apart. The lower bearing dust cover is flush with the spindle housing.

[coherent]

Glad you eliminated the issue! No play by hand doesn't mean there won't be play under machining pressure, so I'd keep an eye on it and just check for play down the road a bit.

Like I mentioned the specs on these change or differ and I don't think quality control is great... as long as they can assemble them and it works, they ship um out.

[lcvette]

Should be zero play!!!!!!! Should be pure loaded. I would re-examine everything!

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[Signal9]

argh!

I will pull spindle and put more pre-load on the top bearing.

[lcvette]

Where are you putting the shims? I gave up on the ac bearings as I went through several sets and they continuously had run out after a few weeks of use. I went with Nachi tapered roller bearings and once they seated in, I run them at 5400rpm for long durations and they barely get warm any more and my run-out is at zero with a .0005".



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[109jb]

I personally don't understand the necessity of going to angular contact bearings for the spindle. For one they are not a drop in fit. Then considering the maximum speed ratings for the bearings, the spindle bearings aren't the limiting factor anyway. The bottom bearing on the upper gear has the lowest speed rating of the 4 bearings for the spindle/spindle drive. I searched for the lowest speed ratings I could find on the stock bearing sizes used in the G0704, and found this:

Top of Gear: 6209ZZ bearing - 7500 rpm
Bottom of gear 6007-2rs bearing - 6800 rpm
Top of spindle: 32005 bearing - 8300 rpm
Bottom of spindle: 32007 bearing - 7000 rpm

The bottom bearing on the gear is the lowest I could find but is still at 6800 rpm and is a higher speed than a G0704, even with a belt drive, needs to normally run. So, unless running uber-high spindle speeds, I see no speed benefit.

So if it isn't a speed thing is it for improving runout? My own G0704 has very low runout from the factory. I don't remember the exact numbers, but remember measuring the spindle runout and being impressed with how good it was. Are others finding excessive runout with the stock bearings?

Is there another reason I am missing?

[lcvette]

My stock bearing sucked and didn't last, more a quality of metrical thing I think. The AC bearings have a lower load rating then the tapered bearing too. I am satisfied with the nachi tapered units so far, and like I said my run-out is excellent and actually improved after break in. I ran them in with kluber grease, then loosened, cleaned them out replied grease and re preloaded and they run tight and cool and very quiet and smooth. Not sold on single row AC Bearings being an upgrade any more after going through several sets and developing run-out in all of them. Just my experience and 2 cents worth. Also eliminates shims and other potential alignment issues along with not being a proper fit.

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[Signal9]

I followed the many videos available on using the shims from Mcmaster Carr. The upper bearing, the shims sit on top of the bearing. the lower bearing, the shims are placed onto the spindle shaft first and then the larger ac bearing is pushed onto it.

Anyways, I took the spindle assembly off and gave the upper bearing preload nut ontop a tug and the vertical play is all gone.

Reinstalled everything and don't have any crazy noises.


I have a belt drive on mine as well 6k is the maximum speed. The factory bearings from what I read would not tolerate this speed and generated alot of heat.

Going to measure the run-out this weekend. If its horrible, I may go with those Nachi taper bearings if my run out is really poor.

The mill head gets about 115 degree with load. 35 minute milling cycle at 4000 rpm.

Ambient temp was 85.

[Signal9]

Swapped out the ac for taper and my vertical play is gone after pre-loading the bearing and my run-out is very minimal as well.

Did the bearing break-in and will check run out after it all cools down. spindle temp at 4k rpm was 105 degrees during break-in.

Weiss motor 134 degrees.
Ambient Temp was 85 degrees

[lcvette]

Yeah, I'm a fan of the tapered rollers.. just be sure to perform maintenance once in a while if your running it alot, you want to make sure you keep some quality grade bearing grease on them. I'm a fan of the kluber, seems to do really well on the tapered bearings. My run-out was nuts perfect with these bearings after a few hours of running and readjustment, although I was using a shared .0005" test indicator. I just got a new test indicator, Brown and Sharpe .00005" bestest indicator, I think I will check run-out with it and see where it is now days. Will report back tomorrow!

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[Signal9]

Lcvette,

I still had a ton of Kluber left over from the AC bearings as well. So ironic, I also have the Shars Test indicator as well.

Could you take a temp of your spindle next time you got it running around 4k rpm?

Thanks

[lcvette]

I don't think I have a temp gun, but I can tell you they got HOT during break in, all part of the bedding in though from what I've read. When they started getting really hot I would back it down a few thousand rpm until they cooled a bit and stabilized, then I would go back up, I did this several times until I got to max rpm. After a few times of that they would get so hot at max rpm. Note I can run them at 5400rpm and they never get much more than warm to the touch.

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[Signal9]

For anyone interested in going back to higher quality taper bearings than stock.

32005 Nachi Tapered Roller Bearings Japan 25x47x15 8300 rpm max w/Grease

32007 Nachi Tapered Roller Bearings Japan 35x62x18 6200 rpm max w/Grease

I bought these from VXB Bearings Online Store The Ball Bearing Supplier & Distributor

[Signal9]

Day two results

4k RPM spindle temp was 88 degrees!!

Ambient temp was 83 degrees.

Previous results from Day 1

4k rpm was 105 degrees.

run-out is minuscule.

[lcvette]

Day two results

4k RPM spindle temp was 88 degrees!!

Ambient temp was 83 degrees.

Previous results from Day 1

4k rpm was 105 degrees.

run-out is minuscule.

Nice!! Same thing happened for mine and have been running smooth since! I also noticed a better part finish then the ball bearing AC units gave.

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[dimitrislamia]

For anyone interested in going back to higher quality taper bearings than stock.

32005 Nachi Tapered Roller Bearings Japan 25x47x15 8300 rpm max w/Grease

32007 Nachi Tapered Roller Bearings Japan 35x62x18 6200 rpm max w/Grease

I bought these from VXB Bearings Online Store The Ball Bearing Supplier & Distributor

Gooday, i have a VF25L mill that is pretty much the same mill as the Grizly, i sadly have 0.03 mm runoun in the MT2 taper and i am thinking of changing the bearings, do you think that changing the bearing could fix the problem?

[Signal9]

Dimitri its hard to say. I did not measure run-out prior to swapping to A/C bearings when I realize I had a large amount of run-out compared to other A/C Bearing converted G0704.

That being said, using the taper roller bearings reduced my run-out to nearly nothing.


If you can't live with the current run-out and you have done everything else to trouble-shoot, I guess investing another 50.00 isn't going to break you especially if it corrects your run-out.

However I would check out the videos that Hoss and other's have posted in u-tube to make sure your testing the spindle like everyone else. because if not, then its an orange to apples comparison.