Noisy Spindle Bearing

Gentlemen

I am cleaning up a recently acquired 1969 10EE 30" lathe. This lathe is equipped with a Baldor 5HP VFD drive (no back gear). This was originally a 480v machine and I have been testing it on single phase 480 temporarily until I can equip it with the proper VFD. I have a Fuji ACE VFD which can drive this motor from 240 single phase and am looking forward to getting this set up and operating and expect it will be a good setup.

Unfortunately, I made an unwanted discovery. I notice that when operating the spindle at low RPM (under 100) the pulley -side of the spindle bearing is making a bad sound approximately once every 5 revolutions. Something to do with the bearing race I am sure but that's as much as I know. I can't attach a video unfortunately. I removed the flat belt and am only turning the spindle.

The spindle sounds 'normal' at higher speed, although my expectation was it would be more quiet than it actually is.

I have checked the oil level (single sightglass) and the operation of the tach gear scraper and little mini-reservoir at the top an that appears to be OK.

So I think the only course is to remove the spindle and take a look.

1. Can someone with decent skills perform the disassembly / reassembly? (i.e. me)
2. Are special tools required?
3. Is sanity required?

Thanks
Gerry Block

From my experience with a CVA (same same but different) you will need to make a special puller for jacking the spindle out. It uses studs that screw into the spindle nose cover bolts and then a long piece of allthread down the spindle with a washer and nut at the pulley end that you tighten to slowly push it out

(After undoing the collar nuts that retain everything)

Its not that bad a job just take it slowly and don't get frustrated.

Do not pick up a hammer.

Sent from my SM-G973F using Tapatalk

Do some searching on here. A fellow did a very good detailed write up some time back.

OK got it. I will look for that thread and study it. Thanks

Removing is easy, just make sure to unscrew the inch and half set screw on the back of the headstock. If you get new bearings here is the info, read all the way thru.

"new" spindle/ new bearings, 10EE WIAD old style rear bearing headstock

BSCustoms said:

Do some searching on here. A fellow did a very good detailed write up some time back.

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10ee spindle removal

Thank you Cal. I think I have all the links now to study. I have been monitoring the Monarch forum for quite a while, but I admit I find searching on PM not easy when I'm looking for something specific. Works better to go back to Google and it finds the thread.

I was confused about the simplest detail - removing the drive pulley assy - until I realized that because the lathe has a collet closer there is an drive tube threaded on the end of the shaft which also serves as the jam nut for the drive pulley. It has hole for a small johnson bar to unthread it, but it won't easily budge so I'll work on that one.

Thanks all for assistance. Great forum.

It is mostly if no all coming from the rear - I can hear it even more clearly by positioning a microphone there and listening. I saw in a related 'removing the spindle' post that someone in the act of removing the spindle got the rear bearings out very early in the extraction process. I will take this approach, and see about swapping just the rear bearing to see how far that gets me. I have not measured the accuracy, which I will do to the best of my ability. I am more interested in the machine running quietly than in any theoretical accuracy, just on principle. I'm sure the two things are related.

In the mean time, I spoke with General Bearing. They still have 4 sets of the front bearings left, and guess what - they want to sell me all 4 sets. They are saying that the one-off price is $1675 but $1200 for all 4. I think this is pretty negotiable. Any interest on anyone's part for the others? My personal guess is that they can be gotten for the 'original' price of $1000 a set if I order all of them at one time.

Regarding the spanner - yes, I'll make one! Its already out of round from somebody doing this at least once.

Gerry Block

Well, let me talk to those guys a little more and see what they will really do. I have read years worth of chatter about these bearings on this forum and the only thing I know for sure is they are hard to find. There is always the envious story of someone finding a NOS pair in the back of the next guy's workbench, but that stuff doesn't happen to me. I'll have to buy them.

I'm going to take copious notes about my disassembly which at the end I'll publish for the next guy. But nevertheless I did finally get the rear drive components removed off the spindle and cleaned up the gunk on the shaft to take a gross measurement. (BTW I don't have a really suitable test indicator or even a good enough stand - I'll have to rectify that). I of course isolated the motor and it is perfect - and silent.

The drive end of the spindle shaft looks like it is moving +/- .0005 once per revolution. I won’t pass any judgement about the cause until I replace the rear bearing pair, which need replacing judging by sound.

The front of the shaft is moving something on the order of +/- .0001, once per revolution at the mouth of the taper. I am not yet going ascribe what is the cause and what is the effect. I would guess the front could be moving due to the rear, or vice-versa, or the spindle could be bent which I wouldn't think would be likely, or its not clean, or....

So first I will get the rear bearing pair and see if I can remove/replace without disassembling the entire spindle, as I learned happened to one fellow by accident.

A 1969 has (should have) the angular contact bearing pair for the rear bearing. eBay has high precision bearing pairs in virtually every size for cheap, start looking there. The issue with the front pair is the flange, that is the reason eBay isn’t good for it. Even so, when I was buying my front pair, there were a couple of 2MMF/2MM pairs on eBay, just not the right size.

bll230 said:

A 1969 has (should have) the angular contact bearing pair for the rear bearing. eBay has high precision bearing pairs in virtually every size for cheap, start looking there. The issue with the front pair is the flange, that is the reason eBay isn’t good for it. Even so, when I was buying my front pair, there were a couple of 2MMF/2MM pairs on eBay, just not the right size.

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Yes that makes sense. In the mean time I took the time to get a better dial indicato(- +/-4 mils) and spent more time cleaning the shaft where I am measuring. So now I am in the position of having better information and looking a little silly as a result. My original problem - the sound - is still there, but the runout is totally different than I reported. On the rear shaft there is no discernable movement at all on the .0001/division dial indicator. I looked at it under a magnifying glass to be certain of this statement. This is true even as the rear bearing makes its 'once every five revolution' sounds. So the runout is unmeasurable by me.

In the front, there are some small dings on the inside surface so if I pick the best spot I get +/- one needle width (+/- .00001?)

With the 5C collet chuck installed (after a thorough inspection and cleaning of the mating surfaces) my best visual estimate is +/- .00002".

So it sure looks like I should tuck my tail between my legs and leave it alone.

I also have installed the Fuji Frenic VFD and that seems to work very well although a little convoluted to program (unlike the Baldor). I did not enable the feedback encoder. I don't believe it will provide any advantage. The VFD control inputs are interfaced directly to the drum switch and a single-turn linear potentiometer was installed in the lathe speed control box as the VFD speed control. So the operation of the lathe is very much like the original design - turn on the power, set the speed, move the handle.

The electrical interlock is provided that will not allow power-up if the handle is not in 'neutral' position.

Gerry

Regarding the encoder. The way I understand it the new generation VFD's actually has a good idea of where the motor armature is. And of course the synthesized 3 phase output is spot-on in frequency. So as long as the armature stays locked to the magnetic field, as a system it should remain very accurate in speed. The inner loop feedback in the VFD is occurring in the waveform generation domain (probably at a very high rate of in excess of 1Khz) and making corrections to keep the armature in lock.

So that is my story. When I get motivated I will make some tests and measure the speed performance (monitoring the encoder output with an oscilloscope) in both modes and see what is actually happening. But let me get some of my other issues resolved, like getting those nasty pulleys back on!

And by the way, the internal tach generator driving the speed meter is spot on.

Gerry

Regarding VFD

thermite said:

They do, indeed, or more usefully, whether the motor is deviating from the optimal, "sensorless vector" is it?

Anyhoo, "new technology" is easily old enough to vote, and works very well, long-since. AC motors are at-core"frequency animals" that care more about attempted sync, HP and torque to acccomplish it are "chasing" the goal.

DC motor is the opposite. Torque animal. RPM is actually just a byproduct.
Comparable integral feedback for DC is the "IR" loop. but... use of even an analog tachogenerator can improve RPM-holding under load tenfold if not twentyfold, if not a hundredfold.

Downside is the analog tacho costs from $250 to $2500, a Reliance MOUNT for it is over $250! You don't even want to KNOW that a 5 HP Reliance RPM III Dee Cee motor can have a MSRP of over $11,000 USD?

VFD + 3-P motor is right decent value for poverty-biscuit budgets!

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Been sidetracked by some other things. After deciding to leave the spindle bearings as-is, I did perform the VFD installation of the FUJI VFD obtained from Marshall Wolf. In its basic form it works very will but the low speed performance is going to require attention. There is a 'low speed torque boost' setting which I have not played with yet. The performance is improved by enabling the 1024 ppr tachometer input, but my belief is it can be adjusted to work well without the tachometer.

Everywhere I look it appears a ham-handed mechanic has tried to 'maintain' this lathe over the years without the requisite skills knowledge or curiosity. So I am doing what I said I wasn't going to do, that is take it mostly apart. I am now sidetracked on the oil pump and plumbing. One positive side effect is I'll probably be able to do a better paint job than I was anticipating.

This forum has absolutely fantastic information, thanks to all contributors.

FYI - don't forget to remove the setscrew from the spindle lock nut before attempting to loosen it. Also, on mine there is a pin (under the paint where you can't see it) in the back near the reversing switch compartment. If you don't remove it you can't extract the spindle (spindle will move but not slide out).