# Lathe Spindle Runout Measurement



## AndySomogyi (Dec 19, 2019)

My Clausing 5428 had a LOT of damage on the spindle from a previous owner who tried to disassemble the machine with a hammer and chisel. I pulled the spindle and cleaned up the burrs and high spots with a cylinder lap, but I had concerns that the spindle might be damaged or I might not have lapped the bearing journals concentric. So, I re-assembled the headstock, and adjusted the preload, so there is a very slight drag by the bearings, a good spin of the spindle spins it just about a full turn, which is about what the Clausing manual recommends for preload. The bearing races and rollers looked surprisingly good, so I just cleaned and reassembled them.

So, I took a series of measurements here, and I'm seeing about 2-3 tenths of jitter in the indicator. I'm interpreting these readings as jitter, in that I do not see any out of roundness. The bumps of the dial indicator never bump in the same spindle rotation angle. Hence, I'm conjecturing that these variations are caused by bearing rollers either slightly worn, or possibly some variation in the bearing surface or rollers.

The one reading I have a slight concern was the one on the tail end of the spindle, this showed a variation of about 6 tenths or so, however there was some damage on the tail of the spindle, it might have been dropped, or something impacted it at some point. So, possibly that damage is what's causing the larger variation on the readings there.

What do you guys make of these readings, is this excessive jitter?

I'm going to have to pull the spindle out anyways, because I need to make new bushings for the back gear, so I'm not sure if I should install new bearings at this point.

I do have another thread for my lathe build, but I figure this is a very general question and might be of interest to anyone working on lathe spindle.


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## pacifica (Dec 19, 2019)

I would measure on the inside of the spindle ,where the morse taper is and be sure it is 100% clean with no burrs or ridges.


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## AndySomogyi (Dec 19, 2019)

pacifica said:


> I would measure on the inside of the spindle ,where the morse taper is and be sure it is 100% clean with no burrs or ridges.


That's the first thing I did in the video.


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## mikey (Dec 19, 2019)

Andy, the method you're using makes it difficult to determine a) how much run out there really is and b) where it is. I suggest you mark your spindle and also mark something stationary. Align those two marks. Put the tip of your indicator inside the spindle and zero it with the two marks aligned, then rotate it 360 degrees and realign the marks. If the indicator returns to zero, this tells you your set up is repeatable. Now slowly rotate the spindle, watching for the greatest deviation. Note the magnitude of the deviation and mark the spindle so you know where it is. Now realign your initial marks and make sure the indicator returns to zero. Repeat the step looking for the greatest deviation. If it is the same amount and in the same place then that is the amount your spindle is running out. 

Doing measurements in motion or under power tells you almost nothing.


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## AndySomogyi (Dec 19, 2019)

mikey said:


> Andy, the method you're using makes it difficult to determine a) how much run out there really is and b) where it is. I suggest you mark your spindle and also mark something stationary. Align those two marks. Put the tip of your indicator inside the spindle and zero it with the two marks aligned, then rotate it 360 degrees and realign the marks. If the indicator returns to zero, this tells you your set up is repeatable. Now slowly rotate the spindle, watching for the greatest deviation. Note the magnitude of the deviation and mark the spindle so you know where it is. Now realign your initial marks and make sure the indicator returns to zero. Repeat the step looking for the greatest deviation. If it is the same amount and in the same place then that is the amount your spindle is running out.
> 
> Doing measurements in motion or under power tells you almost nothing.



Thanks, yes I did that. On all the planes, I looked to see if the pattern repeats, and it does not. Well, except for the tail end, it does seem to be a genuine high spot there.

I referenced a fixed spot (back gear lock pin), and the error pattern does not repeat with spindle angle of rotation.

Which is why I’m thinking all the jitter here is from the bearings and the spindle is true.

Note, I’m certain this lathe was run with dry spindle bearings for some time because the oiling holes were blocked. I’m thinking about getting new spindle bearings when I reassemble it, they’re not that much, like $35 for the bearings and races each.


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## Chuck K (Dec 19, 2019)

*That sounds awfully cheap for spindle bearings.  Are you sure that is the same class bearing that came in the machine? *


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## AndySomogyi (Dec 19, 2019)

Chuck K said:


> *That sounds awfully cheap for spindle bearings. Are you sure that is the same class bearing that came in the machine? *



Yes, I checked with Clausing, the machine originally sold with automotive class bearings, which are the $35 ones. Higher spec bearings are $55 a piece. Looks like there’s only one class for the race, but two different ones for the bearing itself, all from Timken. 


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## Chuck K (Dec 19, 2019)

Sounds like a no-brainer. At that price I would be installing new bearings.


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## mikey (Dec 19, 2019)

AndySomogyi said:


> Thanks, yes I did that. On all the planes, I looked to see if the pattern repeats, and it does not. Well, except for the tail end, it does seem to be a genuine high spot there.



So, you're saying that you can get the indicator to return to zero and the deviations you're seeing varies from rotation to rotation? If so, then it could be the bearings are shot. I agree with Chuck; I would change them out since you're in there and then confirm the spindle is straight and true.


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## AndySomogyi (Dec 20, 2019)

mikey said:


> So, you're saying that you can get the indicator to return to zero and the deviations you're seeing varies from rotation to rotation? If so, then it could be the bearings are shot. I agree with Chuck; I would change them out since you're in there and then confirm the spindle is straight and true.



Yes, the total indicator runout (readings on opposite sides) is essentially zero. The bearings do feel a little rougher than I would expect when rotating by hand.

The indicator runout readings do not correspond to spindle angle, I think one of the rollers might be worn or something, and as it rolls it might be causing the jitter 



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