# Of spindle chatter and bearings...



## CapnDenny1 (Sep 14, 2021)

I recently bought an Asian lathe of eBay.  I bought an MX-210V.  It has a thru spindle diameter of 1.4", and needed a finished size of 1.1".

But the lathe was just about useless because of excessive chatter.  I asked my brother for help, but he couldn't it out.  He is a machinist, but everything is CNC for his job, so..  I've watched videos and really struggled.  Then one day I was looking for loose stuff, since the videos say that's one of the causes of chatter, and I tried to wiggle the 3 jaw chuck.  Tony amazement it was loose as a goose.  I could easily wiggle the work piece up and down by 0.100" or more!

So I determined the bearing at the chuck is an angled roller bearing.  The bearing at the drive end is a deep groove ball bearing.  That makes no sense?  Shouldn't the drive side bearing also be a tapered roller bearing?  In spite of that I took the spindle out and examined it.  The drive side bearing with the deep groove ball bearings does not slide onto the shaft very easily.  It's OK up to where it is supposed to sit and the spindle gets thicker and appears to have been polished.  But it's just too big to go inside the bearing.  I could probably drive it on, but my understanding is I use the spindle nut to pre-load the tapered roller bearing at the chuck end.  But it has to pull the spindle thru the left bearing.  If it binds up then it won't do a very good job of pre-loading the bearings.

I tried using some Emory paper, but it was slow going.  So I went ahead and put it together and tightened up the nut.  It took a lot of force, but eventually I was able to get it to tighten up, and I could not feel any up and down slop in the chuck end of the spindle.  So put it back together and it was able to cut finally.  I managed to make one of the 4 pieces I needed to make.

It worked until I got to the time I needed to perform a cutoff of the 1.25" aluminum bar.  Then it started to chatter really bad again, and I could see the piece wobbling really bad.  I checked the up and down movement and it was loose again?

It has two nuts on the end of the spindle to lock them.  So I figured they just got loose again.  So this time I used Permatex Blue threadlocker on the threads.  So I got it all back together again.  Went to the cutoff, and at first it was ok, but it started to chatter more and more, and then got really bad again.  I checked the up and down motion, and it was loose.

The nuts were almost impossible to remove with the threadlocker on them?  I had to hammer them off.  And the thing is, there is no way the nuts just backed off.

So I have a new set 2 angled roller bearings, one for each end.  

But what is going on?  

Should I just use the hacksaw to cutoff?

Should I work on the shaft until the bearing can slide on the shaft?

I took the outer race out at the chuck end, and there was a bearing cover between the outer bearing race and the casting?  It's like it was being used as a spacer.

So that is my story.  I guess I will try to put the two new bearings in there.  But Ild like to understand how the bearing can seem tight, then get some chatter, and it loosen up?


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## Superburban (Sep 14, 2021)

Two thoughts. One like you are thinking, the nuts are loosing the assembly. The other, is when things heat up the bearing is expanding ever so slightly, and sliding a bit further on the shaft. 

To test the first, I would mark a spot on the nut, and the shaft, with a dab of paint or something. Then test the lathe with something that will make it work a bit.  

I'll search up info on that lathe, and see if I have any other ideas.


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## addertooth (Sep 14, 2021)

Some bearings are press-fit onto the spindle shaft.  If they are not seated all the way, as the spindle settles deeper it can create enough room to have some slap.  The various videos on upgrading the 7X12 bearings go into this, which is why they suggest you carefully hone enough off the spindle O.D. for one of the bearings to be mobile.  This prevents it from getting stuck on the spindle before getting fully seated.


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## matthewsx (Sep 14, 2021)

Hello and welcome.

My first question is how long ago did you buy this lathe? It sounds like it never worked properly so if you just got it you may want to contact the seller and/or eBay.

We expect Chinese machine tools to be kits to a certain degree but yours sounds like it might be a lemon. There are others on here who might be able to help with something like this, also lots of youTube tutorials. 

John


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## CapnDenny1 (Sep 14, 2021)

First off, I'd like to thank everyone for their replies.  It looks like I found a good place to ask for help.

The lathe is about a month old.  The ebay seller was responsive, and offered to send a new bearing, or $60 refund so I could just source the bearing locally.  I already had a pair of tapered roller bearings on the way.

The bearings I ordered were 30209, or 45x85x21.5 tapered roller.

After I pulled the bearings both from the casting I could see the numbers.  The chuck end was a 30209, so good guess on my part.  I actually measured it.  The drive end bearing was a 6209 RS, which is a 45x85x19 sealed deep groove ball bearing.

I don't think heating is an issue.  But when doing cuts, especially doing a cut off, there is a ton of vibration.  So I can see where it would do the impact hammer kind of thing, and be able to move the bearing, even on the tight shaft.

What is a good way to reduce the size of the shaft to allow it to move through the bearing on the drive side?  If only I had a lathe!

I should probably check the chuck end bearing to make sure it is completely seated as well.


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## C-Bag (Sep 14, 2021)

I had a similar problem with my 9x20 which going through posts methodically here I found out the cure. It was a multi solution as there was a problem with the crossslide gibs too. And the way the QCTP was mounted. Every thing helped get rid of chatter. But it was a long process of elimination.

Mine has tapered bearings on both ends. And from the factory they were both press fit on the spindle. Like you’ve deduced the bearing on the drive end needs to be a slip fit in order to set the preload properly. Since I didn’t have another lathe to take off the necessary aprox .0005 I made a rig to mount the spindle in my drill press and slowly and carefully filed and sanded until I got the proper slip fit. No more problem with adjustment changing. You might have to use a torch to loosen the Loctite. As you see, that’s not at all a good solution.


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## addertooth (Sep 14, 2021)

CapnDenny1,
Pay attention to the jig that C-Bag has shown.  Many like you (including me) only has one lathe.  But, many DO have a drill press.  This is a good way to spin the spindle with both ends supported, to get a more even honing.   You don't need to hone the entire shaft, if you are CERTAIN you got the bearing closest to the chuck deeply seated onto the spindle (half-way will work nicely).  And I do mean ALL they way down.  It is only the bearing furthest from the spindle that needs to be able to move down the spindle with light friction.  This way, preload can be set, and should be consistent.  If you care considering adding a "spider" to your set up, it should be added when you are assembling it.  This way, you aren't adjusting bearing pre-load twice.


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## CapnDenny1 (Sep 14, 2021)

I thought about using the drill press, but I thought, "That will never work!"  But I hadn't considered supporting both ends.  I also briefly thought of using the wood lathe?  Maybe I could use a speed control to slow it down?

There is lots of slop elsewhere I know.  And plan to work those issues too.  But until I fix this problem they are very much secondary to the problem.

Thanks, it's encouraging to see others fix these issues.  it helps also knowing I am on the right track.

I am an EE for 45 years, and worked on my own cars and motorcycles in my younger years.  But this stuff is all a bit new to me.  But that also makes it fun!


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## addertooth (Sep 14, 2021)

CapnDenny1 said:


> I thought about using the drill press, but I thought, "That will never work!"  But I hadn't considered supporting both ends.  I also briefly thought of using the wood lathe?  Maybe I could use a speed control to slow it down?
> 
> There is lots of slop elsewhere I know.  And plan to work those issues too.  But until I fix this problem they are very much secondary to the problem.
> 
> ...


I started life as a Machinist, and over time migrated to EE Engineering work.  So, understand your path.  An understanding of Precision applies to many domains.


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## C-Bag (Sep 14, 2021)

CapnDenny1 said:


> I also briefly thought of using the wood lathe? Maybe I could use a speed control to slow it down?


I would use that in a heart beat. Like one member's tag line says, "tools, not rules". Machining is all about correctly identifying the problem and finding a way to correct it. 


CapnDenny1 said:


> There is lots of slop elsewhere I know. And plan to work those issues too. But until I fix this problem they are very much secondary to the problem.


I disagree. In my lathe's case the slop in the QCTP and crosslide were the beginning of the cure. And as I took care of them I could take bigger cuts and that's where the next domino fell. I actually started with my lathe bits as even though I was already using HSS I didn't have really good optic's to check my grinds. That's why I call it domino's because one thing led to another, to another etc. So proper leveling, alignment of head to bed, grinding angles, proper grinder, good optic's(found a stereo microscope on CL for $40!), then tool post, then crosslide, then headstock bearings and fit to the spindle and finally proper pre load. They are all crucial and without them all you can think you've not cured anything. It was a long process but it was totally worth it. And I learned a LOT.


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## CapnDenny1 (Sep 14, 2021)

I know there are other issues.  But when the spindle bearing was tight, it worked pretty well.  Nice controlled cuts, decent finish, etc.  But then the bearings would move, and it just went to heck.

If I solve this one, then it will be worth it to make the other issues better.  One step at a time.  Otherwise it's too big a problem.


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## Mitch Alsup (Sep 14, 2021)

It seems to me that what you need to do is to insert the bearings and TQ down the lash nuts. 
Do a few turning passes until chatter shows up, the TQ the nuts down again,
Do the above 4-5 times until the bearings no longer seat themselves farther into their housings.

Then let the machine run at 75% rated RPMs for 10 minutes and check bearing temperatures by hand. Too hot, back the nut off by 5º, not even warm, add 5º to the nut.


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## Lo-Fi (Sep 14, 2021)

Swapping bearings


Mitch Alsup said:


> It seems to me that what you need to do is to insert the bearings and TQ down the lash nuts.
> Do a few turning passes until chatter shows up, the TQ the nuts down again,
> Do the above 4-5 times until the bearings no longer seat themselves farther into their housings.
> 
> Then let the machine run at 75% rated RPMs for 10 minutes and check bearing temperatures by hand. Too hot, back the nut off by 5º, not even warm, add 5º to the nut.



Get some quality bearings in it if you haven't already, then follow the above. Also, warming the bearing inner race up slightly will help you seat it initially. Only 100deg or so, nothing crazy, and be quick when positioning it.


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## CapnDenny1 (Sep 14, 2021)

Thanks again, but...  (shows how much I have to learn.)

I was under the impression that once you set the pre-load, you were done.  I've never seen anybody talk about having to re-tighten, and re-tighten?

And as far as heating the bearing.  I also read the suggestion of putting the spindle in the freezer overnight.  I understand that the colder part is smaller and the hotter part is larger.  But, I need at least the drive end to be free to move don't I?  I guess if it is adjusted correctly as I thought it would be, then it doesn't matter how you got it there, as long as the bearings are in the right place.

I think that makes perfect sense for the outer baring races.  To put those in the freezer or even just the fridge.  But both of those move pretty easily.  It's the one on the shaft that is too tight.

On the other hand, if I make it too loose by reducing the shaft, then no amount of tightening can fix that.

OK, too many variables!


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## Lo-Fi (Sep 14, 2021)

A good interference fit is maybe a thou or two at the sizes we're looking at here. Steel expands roughly 1 thou per inch per 100F. Heat the shaft, cool the spindle. Either way you're making life much easier for yourself.

What's probably happening in your case is the bearing race is a rather tight and you're struggling to shift it without some serious force in the nut, which leads to not getting decent preload. Keep at it, you'll get a feel for it. 

This will give you a good idea, much as it's a very different lathe:






Notice he had trouble parting until it was tightened up too, even on a large lathe!


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## C-Bag (Sep 14, 2021)

Being a mechanic by trade and dealing with proper clearances once I got how this thing was supposed to work and getting coherent info I knew what I was supposed to do. I have many different kinds of pullers and an arbor press. The hard part was getting the slip fit on the spindle. It should be noted just like when you are turning a piece of metal to size you need to take the temp of the spindle into account. What won't fit when warm will be sloppy the same temp as the bearing.

 I know this is a lot to take in but ignorance is not bliss when dealing with precision machinery. That's why I do a LOT of studying before I start tearing something apart. Once you have all the info you can also have a better chance of avoiding disaster. 

There is no way the drive side bearing can be adjusted properly when it's an interference fit. Many of us have been there and know this is the product of bad QC at the factory.


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## CapnDenny1 (Sep 30, 2021)

I finally managed to get the new bearings in.  I first had to undo my previous attempts.  I used Locktite blue and it got all over the threads and it hardened.  I used a heatgun and a pick to clean up the threads.

When I pulled the chuck side bearing race out of the headstock, I found a crude spacer in there taking up space.  It didn't look very precise, so I just left it out when I put it back together.  I think it was a bearing cover plate they were using as a spacer.

I elected to not doing any work on the spindle.  It took some work getting the old bearings off, but using my digital calipers I decided the old bearings were tighter than the new ones.  I drove the chuck side bearing past the other bearings high spot just a little at a time on each side.  It went on easier than the old ones came off to be sure.  I just used the threads on the spindle to pull the drive side bearing in, using the old ball bearing as a spacer.  It worked.

I was able to get it to tighten up just fine so far.  I ran the lathe at top speed for a minute or so, and it seemed OK.  I ran out of time so I didn't do any machining yet.  I decided to quit while I was ahead too.

I am afraid to try and do a cut off.  I have a couple parts I need to make.  I almost want to make those first because I need those parts ASAP.  Then I can experiment with the cut off again.

I noticed the bearing seat for the outer bearing race, in the casting of the headstock, has some gouges or creases.  I guess they are voids in the casting.  I am afraid that perhaps the casting is cracked at those points.  Perhaps that is the root cause of the creepage in the bearings?  It seems like if you were making a tool, and your machining uncovered a void in the casting, in about the most important spot in the casting, you would reject that casting.  I guess there's nothing like a quality tool.  And that's exactly what I have.  Nothing like a quality tool!  I guess if I wanted a quality lathe, I should have bought one?

Well, wish me luck.  I think I'm gonna need it.


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## matthewsx (Sep 30, 2021)

Run it and see how it goes, if you're past the time to return it then you have what you have.

That's why I asked about how long you had it in my earlier post. What we've seen time and again on the forum is people buy these machines off eBay and once they get into them it's clear that they're factory seconds (or thirds). I suspect that the foundries supply lots of different "manufacturers" and when one sends back a reject instead of melting it back down they just sell it to someone else.
That's why so many on here advise buying through Precision Matthews or Grizzly, they tend to do quality control and are available to provide support when you need it.

The "shim" on your headstock bearing is a dead give-away that whoever was putting it together knew something was wrong. No, they don't stop and put a big "reject" sticker on them since China is a long way from us and they know many of these tools will never even get used. Typical eBay seller tactic to just offer a small "refund" and stall until your time runs out.

IMHO, if you will be using a lathe for projects in the future it's worth getting a good one. Doesn't have to be the biggest most expensive thing out there but the frustration of dealing with tools which were never suitable for the job isn't worth it to me.

Good luck whatever you end up doing, at least now you have a much better understanding of what to expect and how to inspect your next tool purchase.

John


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## C-Bag (Sep 30, 2021)

CapnDenny1 said:


> Perhaps that is the root cause of the creepage in the bearings?


I would bet not, big time. You get to go however you want but sooner or later the spindle will have to be addressed. Because just as soon as you get it hot right in the middle of some job or afterwards when you go to use it again, it will be loose again. The original Emco these lathes are copied from didn't have the drive side spindle bearing a press fit, it was a slip fit.


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## CapnDenny1 (Oct 4, 2021)

Well I got it going.  It seems to work ok.  I was able to finish cutting off the piece I was doing when it messed up before.  I then finished the drilling I needed to do and started on the 4th of 4 parts I needed to make.

On this last part it started to chatter again, so I was worried, but I didn't have the quick change handle locked down.

So far so good.

Once I get this last part done, I will start to work on adjusting the other parts, removing the slop in the other parts.  The tailstock is not even close to being aligned with the head.  There is an adjustment for horizontal, but not vertically.


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## SeanPruden8 (Oct 7, 2022)

CapnDenny1 said:


> I recently bought an Asian lathe of eBay.  I bought an MX-210V.  It has a thru spindle diameter of 1.4", and needed a finished size of 1.1".
> 
> But the lathe was just about useless because of excessive chatter.  I asked my brother for help, but he couldn't it out.  He is a machinist, but everything is CNC for his job, so..  I've watched videos and really struggled.  Then one day I was looking for loose stuff, since the videos say that's one of the causes of chatter, and I tried to wiggle the 3 jaw chuck.  Tony amazement it was loose as a goose.  I could easily wiggle the work piece up and down by 0.100" or more!
> 
> ...





C-Bag said:


> I would use that in a heart beat. Like one member's tag line says, "tools, not rules". Machining is all about correctly identifying the problem and finding a way to correct it.
> 
> I disagree. In my lathe's case the slop in the QCTP and crosslide were the beginning of the cure. And as I took care of them I could take bigger cuts and that's where the next domino fell. I actually started with my lathe bits as even though I was already using HSS I didn't have really good optic's to check my grinds. That's why I call it domino's because one thing led to another, to another etc. So proper leveling, alignment of head to bed, grinding angles, proper grinder, good optic's(found a stereo microscope on CL for $40!), then tool post, then crosslide, then headstock bearings and fit to the spindle and finally proper pre load. They are all crucial and without them all you can think you've not cured anything. It was a long process but it was totally worth it. And I learned a LOT.





CapnDenny1 said:


> I recently bought an Asian lathe of eBay.  I bought an MX-210V.  It has a thru spindle diameter of 1.4", and needed a finished size of 1.1".
> 
> But the lathe was just about useless because of excessive chatter.  I asked my brother for help, but he couldn't it out.  He is a machinist, but everything is CNC for his job, so..  I've watched videos and really struggled.  Then one day I was looking for loose stuff, since the videos say that's one of the causes of chatter, and I tried to wiggle the 3 jaw chuck.  Tony amazement it was loose as a goose.  I could easily wiggle the work piece up and down by 0.100" or more!
> 
> ...


CapnDenny1 how are you? I am new to the club and  have a question for you! I am trying to avoid this situation as well but I am out of town working therefore I am unable to measure for new tapered roller bearings. My plan is to order asap that way when I finish this job the bearings will be at the house!  I also have the Mx-210v and would like to know if you possibly still have the specs on the bearings please? Thanks


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## markba633csi (Oct 8, 2022)

Post #5 has the bearing numbers for his machine


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