# Spindle Binding When Trying To Bring Tolerance Into Spec.



## jbmauser (Oct 22, 2016)

I posted this in the wrong forum so if the administrator wishes he can pull it or from the beginner forum or here.  I do think there is a remedy just need to grouse a bit I guess. 

I watched a video online and saw how to check for play in the spindle of my SB 9C lathe. I put a bar in the chuck end and got over 4 thou of movement. I put a wrench on the the single bolt on the chuck side to remove it and pull the shims as instructed. The bolt was not very tight so I first torqued it down snugly and checked it again and the play closed to 2 thou but the spindle had a little resistance when turned by hand. I backed it off a tad and it spins by hand. But not free wheeling. I moved to the tail which runs a lot of oil and I found that bolt as not snugged down hard. I took a reading of over 4 thou and snugged it down and it binds on a high spot like the shaft is egg shaped backed it off and it spins free. I have ordered a needle bearing and two hard washers as recommended to replace the fiber bearing. This should cut down on the oil leaking. 

I know it is more than likely the headstock opening that is egg shaped and not the spindle but the fact remains it only binds on a small area as the spindle is turned by hand. So I backed off both front and back bolts till the spindle spins freely with a bit of overtravel when spun by home. When the needle bearing comes in it may hopefully remedy the oil leakage. I do not work in high tolerances (yet) so it is what it is.  I guess the adjustment arrangement where you can only adjust one side of the bearing "CAP" of necessity would create an oval rather than a circle but I would think if it would bind it would bind over the entire radial range not just a 10 to 15 degree point.  discouraged and a bit confused.  JB


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## Bob Korves (Oct 22, 2016)

If it is only binding on one portion of a revolution of the spindle, then the spindle is bent or out of round, probably a bent spindle unless someone was messing with the spindle bearing surfaces.  I do not know the best way to proceed with your issues, probably some one else will speak up here...


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## jbmauser (Oct 22, 2016)

Bent spindle, wow!  I guess I will have to look at the original spindle that I still have.  It was galled when I got the lathe.  I had taken the spindle out of a beat up 36 in. SB that I cannibalized and parted out but kept the spindle as it looked better than the original,  It is scored and now it seems it may be bent.  I guess I will have to build a jig with ball bearing contact points to spin the spindle and check for true.  Perhaps I can run it on my wood lathe to check for a bend.


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## Bob Korves (Oct 22, 2016)

If you have a concentric spindle without runout and concentric bearings, and a very small clearance, it will spin freely.  As the bearings are made tighter it will eventually contact the bearings, pretty much all at once.  If the bearings have a high spot or spots and the spindle runs true, then it will spin freely until tightening it down makes it hit the highest bearing high spot, which will start to rub, continuously if the spindle has no runout.  If the spindle is bent, as you tighten the bearings, it will start to rub intermittently on the first high spot it meets, and only rub on the high area of the bearings.  That appears to be what is happening with yours.

You might want to post some pics of the wear on the original spindle and the bearings.  Sometimes, things that look really bad are not actually a big issue.


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## Tony Wells (Oct 22, 2016)

Before I tore it down, I'd run it to a spot that seemed to bind and check for play with an indicator on the spindle, both front and back. That way you might be able to narrow down the end that actually has the tight spot. One bearing may still have clearance when the other does not. If they both show no movement, likely you do have a bent spindle. If you have vee blocks and a good surface, it may be better than your wood lathe, but that's not a bad idea.


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## jbmauser (Oct 22, 2016)

Tony it is definitely the rear bearing that the shaft is binding in.  I just got back in and shot the original spindle two shots of each end


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## 4GSR (Oct 23, 2016)

Wow! that's not good!  I don't know if you can fix scaring that bad.  I have taken a oil stone and mineral spirits, with the spindle spinning in another lathe, smooth out some of the galling.  The only way you are going to remove it all is to have the spindle reground and superfinished.  Then you have to deal with the headstock casting, which would have to be bored out and bronze bushings made to fit.  Unless, you have one of the older South Bends that have bronze bushings in the spindle.
Mentioned something about a bent spindle?  Get you a set of vee blocks, space them out on the bearing surfaces and check the middle for runout, if ok, move the vee blocks to one end of the spindle, and check.  Keep moving the vee blocks around in different positions looking for runout. If any runout in any one place, could be bent.  Lets hope not.  BTY- you don't need a surface plate to set vee blocks on.  You can do it on your mill table if you have a mill and even use the kitchen counter top, too!


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## jbmauser (Oct 23, 2016)

Update.  I removed the spindle and set it up on my wood lathe and took measurements.  The old spindle which was not in the SB read out 4 thou on each end.   I figure this is the error of the wood lathe.  The offending spindle which is not all scratched up read 8 thou at the tail which is where I was haveing the problem and 4 thou at the head.

I put the original spindle which is pictured above back in the headstock and after adjusting the tightness of the bolts got 3 thou play on each end and no binding when the spindle turns.  It seems there is a bit of a bend in the better spindle.


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## jbmauser (Oct 23, 2016)

Question on spindle condition.  If the spindle has wear or damage as above and there are no rough spots that are "high"  (I ran the spindle over with a file which skates on the hard surface but removed cast iron that had welded itself to the surface)  the spindle should still float on a coat of oil and the grooves that are etched into the spindle should just fill with oil and retain it as there is no radial action to move it to the outside.... Does that sound reasonable.  I have run the smoother spindle for some time with loose tolerances and proper lube.  I doubt the casting has any high spots to further degrade or etch into the old spindle as I am fastidious about oiling.


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## martik777 (Oct 23, 2016)

It should be fine. Do the headstock castings above the journals heat up much? The only other thing I might do is polish that original spindle - start with 400 and move up to 1500 or 2000 grit.


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## Kernbigo (Oct 23, 2016)

take it to a auto rebuild shop and have the spindle od lapped, put it back in the housing and adjust the spindle lift using plastic shim and a torque wrench . Set the lift to around .001-.0015 lift after it is warm. Don't remove any more stock than necessary, all the line don't have to be removed.


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## Tony Wells (Oct 23, 2016)

I think the blacksmith in me would do a reverse scrap-in. Using vee blocks, I'd mark out the "high" points on each journal and remove material at those diminishing spots until I could detect as little as possible TIR. Pick your vee block locations well, and never move them. Then to the polishing phase and get the rest blended and smooth as possible. If the spindle is bent between those two journals, so what? We're talking about a minuscule amount of material to be removed anyway, so if the middle areas stay out, it's no big deal.  It's basically the same things as scraping in a pair of ID journals using a known straight pin to highlight the to-be-removed material. Done it after weldup on truck differentials a few times and it seemed to be fine even with the load they carry.

Use your imagination.


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## jbmauser (Oct 23, 2016)

No the bearing caps do not heat up.  It is all reinstalled now, I think I will run it this way for a time to let the original spindle "run back in" to the headstock.  I will take my suspect spindle to a machinist friend to do a more accurate measurement of true.  thanks all for your remarks.  These issues are not the kind of answers you find in books or youtube.


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## jbmauser (Oct 23, 2016)

Tony, thank you for the information.  unfortunately I do not have the knowledge, tools or even understanding to implement your direction.   I  am a rank novice and I am learning on my own. I have reread your info and I will do some research to understand things like scraping in a ID journal.  Thanks.


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## Tony Wells (Oct 23, 2016)

If you were in my neighborhood, I'd be happy to help with it, but as I recall, we're far apart. What I am describing would require a little finesse, but not a lot. Just think about what I said, take it one step at a time. All you would be doing, in essence, is removing the high spots from the effect of the bend, the center of which you don't know and don't care for what I am describing. 

If you were willing and able to spend a bit on it, you could have the bearing journals sprayed up and reground dead true to each other, and really, that's all that counts for this. After getting the spindle true, of course, the register surface of the chuck and faceplate mount should be skimmed back square with the "new" axis. If the spindle is bent, then that surface must also be out of true.

Maybe someone near you could come to your aid.


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## jbmauser (Oct 25, 2016)

Open question.  given that my original spindle is scored and galled, given that the casting in the headstock has to be scored and galled as well.  Does it make any sense to buy a smooth spindle in good shape and install it int he headstock and simply adjust the shims.  Can the tool perform better with a good spindle in a less than good headstock?


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## Kernbigo (Oct 26, 2016)

No like i stated before, take it to a automotive engine rebuilder shop and od hone the spindle, put it back together and re shim, adjust the bearings to +.001-.0015. After that run some thin synthetic oil like 5- 20, it should work fine it is only a lathe not a precision grinder. I used to rebuild high speed spindles,and this is a cheap fix. If you knew how to scrap i would scrap in the housing, but don't attempt it if you never scraped in bearings before. ( only remove min amount of od stock, don't go for removing all the lines)


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## jbmauser (Oct 27, 2016)

I am sorry I may not have stated my question correctly.  I can buy a replacement spindle for under $100 that is without scoring or galling.  My question has more to do with making such an investment given that the condition of the headstock is poor as evidenced by the original spindle.  I am thinking that the cost to refinish will be equal to or more than a replacement and either way it will go into a headstock bearing surface that is less than ideal.  Is it all worth it?  will it matter to basic operation?


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## Kernbigo (Oct 27, 2016)

no


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## jbmauser (Oct 27, 2016)

Thanks, I take it to mean a clean shaft or the scored shaft will perform the same since the mating surface has not been improved.  One last question before I resign my self to the Lathe's working condition.  If I took my diamond dressing tool, a flat bar type for dressing grinding stones and I mounted it in my QCTP and ran it up to the tail end of the spindle and kissed it like you do with chalk to check for concentrically.  Would that "grind" of a few thou on the high spot and bring that end closer to concentric?  I figure I have nothing to loose with a crude "haircut"  if it would even work.


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## Kernbigo (Oct 27, 2016)

What you said will help but try my suggestion about od lapping the shaft it will make it more concentric than just stoning . Maybe you don't follow what i'am saying but i have rebuilt high speed spindles where i use to work and this is a cheap fix. Like i stated before it is not a precision grinder which i would not recommend this presider.


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## John Hasler (Oct 27, 2016)

jbmauser said:


> Open question. given that my original spindle is scored and galled, given that the casting in the headstock has to be scored and galled as well.


I'd inspect the bore before concluding that it is badly damaged.


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## jbmauser (Oct 27, 2016)

JH, it is scored as well, how badly damaged I don't have any reference from mirror smooth to what... do you know what I mean.  I have no way of saying poor, good, horrible.  I will say the lathe functioned with the bent shaft but she looses a lot of oil.  the play in the rear was about 7 thou.  less with the original scored shaft.   I do not work in high precision.  I am only going to tinker with this and  make some bits.  This is a hobby for an inquisitive mind.


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## Tony Wells (Oct 27, 2016)

Then you're probably stressing too much about it. Overall, as long as it's not really banging around, and doesn't get hot....you should be good to go. Even with the minor tight spot, as long as you are generous with the oil, you should be fine. Save your money and worry for your next lathe. 

I don't think you ever stated whether you are running in straight iron or in bronze bushings though. If so, I missed it.


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## Kernbigo (Oct 27, 2016)

This is what my bearing caps looked l like when they were 80% scraped in, you don't want them to look smooth or they will never hold oil , that what scraping is about.


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## tq60 (Oct 27, 2016)

One of the photos shows what looks like a punch mark so something got it.

But the good news is it really does NOT look that bad.

If yiu have a wood lathe that will allow yiu to spin it between centers yiu can polish it up.

First you need to carefully clean it to remove anything dug in.

Next is get a like new flat fine file and very lightly slide it over the nick in the photo.

Next is paint it with a felt tip pen and let it dry well.

Find a flat stone and gently rub the area to now check for high spots.

Low spots or holes left from nicks just hold oil.

Once all high spots are gone spin it up and give it a polish.

Clean up bushings in the caps then repaint with felt tip pen and assemble loosely and spin spindle and tear down to see how the interface between the parts look.

Again focus on high spots.
Assemble and retest.

When it feels good paint it again and tighten everything and turn spindle just one turn and tear down to check again.

Polish as needed then correct shims as needed.

If you are missing any yiu can make them out of soda cans.

Cut with a good scisors.



Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## jbmauser (Oct 27, 2016)

Lots of info to digest.  I took my spindle to a friend who has some serious machines and the ability to take much better measurements to see the most accurate condition of the "bent" spindle.  To all of you who spoke of bearing caps etc.  this lathe has no bearing caps the spindle rides in the cast iron headstock with only a single bolt and slit which contains spacers to adjust for clearance.  This is a South Bend model C workshop lathe from the early 40's.  Any damage to the casting from the scored spindle in the images I posted remain no mater what improvement is made to the spindle.


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## Kernbigo (Oct 28, 2016)

When you polish a shaft with a stone or paper you only follow the out of round you have now, you have to od hone the shaft to get it concentric again.


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## tq60 (Oct 28, 2016)

Cast iron bushing explains the pock mark in the photo.

That is one reason to not use air to clean as it may have got a chunk of something in a gap then sucked it in.

So focus only on locating high spots then polish it up but a mirror finish is not the goal here as it would require too much material removal.

The goal is to remove any rough edges that act as cutting edges.

Inspect the bushings with a magnifying lens as they can hold nasties between the ridges as well as in the surface.

Use 600 grit with solvent or steel wool to avoid leaving abrasives from the paper behind.




Sent from my SAMSUNG-SGH-I337Z using Tapatalk


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## jbmauser (Oct 28, 2016)

Thanks again for all info.  As to polishing.  Let me restate my situation as threads tend to wander.  I have 2 spindles for my lathe, one pictured is the original and it is scored and galled.  The second came from a beat up 9 in. lathe that I parted out and kept the spindle as it only had a few scores on the spindle.  That is the spindle I had put into my lathe as it was a cleaner surface but turns out it is bent. I found that out when I tried to bring the spindle into tolerance adjusting the headstock shims.  I can work on either spindle to improve their condition or I can buy another on eBay for under $100 that is without score marks and hopefully is true.  The condition of the scored spindle reflects the condition of the headstock bearing surface.

Recap of info I have received is to improve the scored spindle I can file (which I had done to remove any fused cast iron bits) stone and polish.  For the bent spindle I should have it honed by an engine shop.  That would bring it to concentric with the chuck end of the spindle and then adjust the shims to bring it into spec.  

Lastly, my concern is that any spindle improvement or replacement will still be held in a headstock iron bushing that is scored with no economical improvement. And the lathe will run with either flawed shaft, albeit with a lot of oil consumption.  A suggestion to use a heavier oil leaves me to wonder if it will wick through felts but that is another thread for anther time.  For now I wait on my friend to see the exact condition of the bent shaft.


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## John Hasler (Oct 28, 2016)

I'd stick with the old shaft: it doesn't look that bad to me.  I'd clean it up just enough to make sure it has no protruding lumps or sharp edges  and is round.  I'd do likewise with the headstock holes.

How much oil does it leak?   You might be able to reduce the leak rate by fabricating seals to back up new felts.  Those machines were designed to leak some oil: it's called a "total loss lubrication system".  Don't try to stop it completely.


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## 4GSR (Oct 28, 2016)

You mentioned in one of your post that the South Bend lathe 9C 1940 model was a top oiler.  Anything built after 1939, the headstock was designed to be a recirculate oil system.  You fed it oil from a oil cup located on the sides of the headstock just under the journal bearings.  Never heard of a bent spindle on a 9" lathe before.  Last thing to ask, did you try to install the spindle without the bull gear and pulley, but with the thrust bearing installed, to check the fit with the bearing journals?  You could get the bull gear cocked on the spindle and it run like a bent spindle syndrome. Ken


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