# Bad motor or spindle bearing going bad?



## Brento (Apr 2, 2022)

I was drilling into some Aluminum to make some stand offs for my DRO scales. As i was drilling the motor started to bog down and slow down like it was going to stall. Even if i let up. The video i posted still does it without any cutting. I went to the next speed down when i used a parting tool and it didnt do it which is strange as that is a higher cutting pressure? I am not in back gear and the bull pin is engaged to the cone pulley. Im hoping maybe the belt was a little loose as well? It is a new belt so it could be stretching?


View attachment FullSizeRender.MOV


I have felt kits to the whole lathe and i havent taken the headstock apart yet. The left bearing was a warmer then the right bearing. I have oil in the cups but i know the right side soaks in much more then the left side.


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## markba633csi (Apr 2, 2022)

Are you sure the countershaft isn't binding up?
-Mark


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## DavidR8 (Apr 2, 2022)

What's it sound like with a bit less belt tension?


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## hudstr (Apr 2, 2022)

It would help if you disengaged the gearbox to reduce the noise. The rhythmic clunking doesn't sound very good. It seems to stop uncharacteristically fast if its a regular single phase motor like something is binding or heating up and reducing clearances.


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## woodchucker (Apr 2, 2022)

Brento said:


> I was drilling into some Aluminum to make some stand offs for my DRO scales. As i was drilling the motor started to bog down and slow down like it was going to stall. Even if i let up. The video i posted still does it without any cutting. I went to the next speed down when i used a parting tool and it didnt do it which is strange as that is a higher cutting pressure? I am not in back gear and the bull pin is engaged to the cone pulley. Im hoping maybe the belt was a little loose as well? It is a new belt so it could be stretching?
> 
> 
> View attachment 402854
> ...


When you say you have felts... You've never changed them in the headstock? How many years?

When I took my lathe apart, the felts were incapable of moving oil, they were hard, black and had no wicking capability.
if you haven't done the job, and it's never been done while you owned it, and you don't know when the last time was, IT'S TIME..
I can not stress that when you get a machine, it's a good idea to go over it completely.  You get to know it, you know when maint was done.


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## Brento (Apr 2, 2022)

woodchucker said:


> When you say you have felts... You've never changed them in the headstock? How many years?
> 
> When I took my lathe apart, the felts were incapable of moving oil, they were hard, black and had no wicking capability.
> if you haven't done the job, and it's never been done while you owned it, and you don't know when the last time was, IT'S TIME..
> I can not stress that when you get a machine, it's a good idea to go over it completely.  You get to know it, you know when maint was done.


I have been meaning to. Just have not gotten to it. Idk when the felts were done last. I guess i will be doing that next right after i finish the DRO on the mill.




hudstr said:


> It would help if you disengaged the gearbox to reduce the noise. The rhythmic clunking doesn't sound very good. It seems to stop uncharacteristically fast if its a regular single phase motor like something is binding or heating up and reducing clearances.


How do you disengage the gearbox when you are not using it? The clunking may be the belt lacing as well. One person mentioned to me that my thrust bearing could be to tight and someone else said to take some of the idle gears off and see if the leadscrew moves freely.


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## woodchucker (Apr 2, 2022)

Brento said:


> I have been meaning to. Just have not gotten to it. Idk when the felts were done last. I guess i will be doing that next right after i finish the DRO on the mill.
> 
> 
> 
> How do you disengage the gearbox when you are not using it? The clunking may be the belt lacing as well. One person mentioned to me that my thrust bearing could be to tight and someone else said to take some of the idle gears off and see if the leadscrew moves freely.


you use the reverser. You put it between gears.. its on the left under the side cover.. just find a neutral.  I only run my gearbox when I need a feed. if I am free turning or facing it's in neutral.


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## woodchucker (Apr 2, 2022)

so btw, I had my headstock lock up... when I rebuilt it I used a teflon lube initially then oil  between the spindle and cone pulley for back gear and it was great. But people said no you have to use grease... WRONG!!!!... I greased it and it overheated in back gear. I then tried the super lube after taking it apart. some said that was what you needed.   well again it locked up.  I took it apart again, cleaned it, and have used oil ever since... no problems... 

But I will say I was able to confirm it was the head, because I release the belt and was unable to move the spindle...
is your spindle tight when it stops?


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## Brento (Apr 2, 2022)

@woodchucker Ok i can take it off so it is in neutral when not being used. I think i will take your advice and do the headstock next. The apron runs good and doesnt lose a lot of oil nor use a lot. Seems to stay in a good condition but i will do the apron and the gear box as i go. If i remove the belt and the headstock is not in back gear i can move it completely fine. My back gear has oil in it. I feared it having grease bc i heard the same stories you heard. And my back gear i pretty full bc i could hardly put any oil in it when i took the screw out. I may even open the screw and suck some oil out.


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## woodchucker (Apr 2, 2022)

Brento said:


> @woodchucker Ok i can take it off so it is in neutral when not being used. I think i will take your advice and do the headstock next. The apron runs good and doesnt lose a lot of oil nor use a lot. Seems to stay in a good condition but i will do the apron and the gear box as i go. If i remove the belt and the headstock is not in back gear i can move it completely fine. My back gear has oil in it. I feared it having grease bc i heard the same stories you heard. And my back gear i pretty full bc i could hardly put any oil in it when i took the screw out. I may even open the screw and suck some oil out.


I would leave the oil in there.
So your spindle is free after it shuts down, your not locking up?
well then maybe it is the countershaft. Is that able to move when it shuts down? is it tight?

have you been oiling the countershaft?


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## Brento (Apr 2, 2022)

I oil the countershaft every time. I have not check it to see if it is tight or not and i do have a broken oil cup on the one side. Id like to get some gravity fed oilers for the countershaft. Can only do so much at once though right! Lol


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## woodchucker (Apr 2, 2022)

Brento said:


> I oil the countershaft every time. I have not check it to see if it is tight or not and i do have a broken oil cup on the one side. Id like to get some gravity fed oilers for the countershaft. Can only do so much at once though right! Lol


well just try and figure out where the problem is..
that's the first step..  lets get you running again.

then you can deal with the long term issues.
is the motor free spinning after it locks up..
something is causing the slowing, something is on it's way to a hard lock up. its heating up and expanding and on it's way to seizing.

I may be due for a felt change on the spindle.. did it in 2014.. and it's been used quite a bit. It's really not a bad job.
Your ways look great.. mine was used in production it seems, and they are rough...

You must have an older model closer to mine, because of the head bolts. later models went to socket cap screws I think.

edit: but I see you have a socket head cap on the cross slide to the apron... that doesn't look right... maybe the fillister head screw was replaced, or maybe they went to that..


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## Brento (Apr 2, 2022)

My ways are worn on the triangular faces but not terrible no. I am not sure what year mine is but id love to know the year. Tmr i will run the lathe and run it until it does that again and check the motor and the countershaft. The motor was cold to touch. I did not check the countershaft. After it did that i ran it after and parted off my part twice and never had the problem. I think i am going to take your advice as i said and tear the headstock apart in the next week and put new felts in and change the thrust bearing to a needle thrust bearing. I have a lot of potential work coming in from a customer and i am assuming a lot of it will be lathe work for motorcycle parts.


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## Brento (Apr 2, 2022)

I did happen to tighten the belt a little as it is a new belt and i think it still had the issue.


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## hudstr (Apr 3, 2022)

You can probably figure out what year it is from these sites by finding the closest serial number to yours.


			South Bend Lathe Serial Numbers
		





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						South Bend Lathe Works - Serial Number Registry | VintageMachinery.org
					





					vintagemachinery.org


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## matthewsx (Apr 3, 2022)

Belts only have to be tightened enough that they don’t slip, anything else is excessive.

do the maintenance required, go from there.

John


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## Brento (Apr 3, 2022)

Ok so update. I check it again. The lead screw is loose and smooth. I put the lead screw in idle position and it still does it. I ran it until it happened and the check all shafts for mobility and the countershaft motor and spindle seem to be fine. I did not loosen the take up collar yet but someone said to loosen the spindle bolts up top a 1/4 turn when it does it. Bingo it goes back to normal when i loosen the bolt a 1/4 turn.  I am guessing that left bearing in the cast is tight or not getting enough oil.


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## woodchucker (Apr 3, 2022)

Brento said:


> Ok so update. I check it again. The lead screw is loose and smooth. I put the lead screw in idle position and it still does it. I ran it until it happened and the check all shafts for mobility and the countershaft motor and spindle seem to be fine. I did not loosen the take up collar yet but someone said to loosen the spindle bolts up top a 1/4 turn when it does it. Bingo it goes back to normal when i loosen the bolt a 1/4 turn.  I am guessing that left bearing in the cast is tight or not getting enough oil.


Sounds like you need to make a shim.. Not hard, the hard part is getting it in there. The way the shims are, they are stuck together and you peel them off.. A nice design. I needed an in between size and made my own.  That's a good find... Now is it heat related because its not getting oil, or is it just too tight???


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## Brento (Apr 3, 2022)

woodchucker said:


> Sounds like you need to make a shim.. Not hard, the hard part is getting it in there. The way the shims are, they are stuck together and you peel them off.. A nice design. I needed an in between size and made my own.  That's a good find... Now is it heat related because its not getting oil, or is it just too tight???


Thats is where i am unsure. I feel like i hardly put oil in that cup and the cup on the right just drinks it up. I can make a shim to get put in there but my question is how do you find how much shim you need. I think i am still going to take the headstock apart and service it bc that is one more part on the lathe that has been taken apart and cleaned. I was thinking maybe an extra 3 thou for the shim would be ok?


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## hudstr (Apr 3, 2022)

Follow the "keep your lathe in trim" instructions. Put an indicator on the spindle, stick a stick in the end and pull up. There needs to be between 1-2 thousandths of movement. Shim as necessary to get that clearance. 

If you never need to fill up the rear bearings, then the oil probably isn't getting used and you need to clean it out and replace the felt.


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## Brento (Apr 3, 2022)

Thanks everyone.


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## Brento (Apr 11, 2022)

To update everyone i have a good looking spindle and bearing from what it looks like. I do have a missing tooth on my small back gear though. That kind of sucks as idk what im going to do with that at the moment.  I will get some pictures of the spindle bearings and the gear.  I am thinking of taking some mineral spirits and flushing the bearings out.


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## woodchucker (Apr 11, 2022)

Brento said:


> To update everyone i have a good looking spindle and bearing from what it looks like. I do have a missing tooth on my small back gear though. That kind of sucks as idk what im going to do with that at the moment.  I will get some pictures of the spindle bearings and the gear.  I am thinking of taking some mineral spirits and flushing the bearings out.


That's great.
*How did the felt look?*
Did you remove the head off the ways?
If you are going to flush the bearings with mineral spirits , take the head off (2 bolts underneath), flush with mineral spirits off the ways.
turn it over and drain. do it again and drain... (when I say drain I mean turn the head over and let the MS come out of the felt holes)
Or use a tube attached to a large hypodermic needle think horse type)


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## Brento (Apr 11, 2022)

The felt was black but not hard. Id like to not take the headstock off the bed right now. So i will put something in the holes to drain. Debating on what to do for the bad gear right now. I currently dont have gas for torches to braze material on and dont have gas for the welder. I have a 110 stick welder with some brazing rod i could maybe use. Tonight i will clean up the headstock casting and take the the rest of the stuff that really needs to be cleaned to work.


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## woodchucker (Apr 11, 2022)

Brento said:


> The felt was black but not hard. Id like to not take the headstock off the bed right now. So i will put something in the holes to drain. Debating on what to do for the bad gear right now. I currently dont have gas for torches to braze material on and dont have gas for the welder. I have a 110 stick welder with some brazing rod i could maybe use. Tonight i will clean up the headstock casting and take the the rest of the stuff that really needs to be cleaned to work.


so in case you are not aware.
You have the felt hole
And right at the edge of the bearing is a little weep hole for the oil go drain back into the head.
That's a pretty small hole.


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## Jim F (Apr 11, 2022)

Brento said:


> The felt was black but not hard. Id like to not take the headstock off the bed right now. So i will put something in the holes to drain. Debating on what to do for the bad gear right now. I currently dont have gas for torches to braze material on and dont have gas for the welder. I have a 110 stick welder with some brazing rod i could maybe use. Tonight i will clean up the headstock casting and take the the rest of the stuff that really needs to be cleaned to work.


You can get a gear on fleabay, just turn yours down for a tight slip fit.
See my backgear post.


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## woodchucker (Apr 11, 2022)

woodchucker said:


> so in case you are not aware.
> You have the felt hole
> And right at the edge of the bearing is a little weep hole for the oil go drain back into the head.
> That's a pretty small hole.


btw black and not hard means it was probably oiling. If it gets hard or singed it's not oiling.
So your original problem was probably solved by your loosening the spindle nut....  and you didn't have 2 problems.


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## Brento (Apr 11, 2022)

woodchucker said:


> so in case you are not aware.
> You have the felt hole
> And right at the edge of the bearing is a little weep hole for the oil go drain back into the head.
> That's a pretty small hole.





woodchucker said:


> btw black and not hard means it was probably oiling. If it gets hard or singed it's not oiling.
> So your original problem was probably solved by your loosening the spindle nut....  and you didn't have 2 problems.


Yea i think it needs a shim. I will find out after i put it back together. I have all 4 clips for the weeps holes and they are all clear.
@Jim F i saw your post for the back gear. It is an option just not sure if i want to go that route yet. I only have this lathe as well.


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## woodchucker (Apr 11, 2022)

Brento said:


> Yea i think it needs a shim. I will find out after i put it back together. I have all 4 clips for the weeps holes and they are all clear.
> @Jim F i saw your post for the back gear. It is an option just not sure if i want to go that route yet. I only have this lathe as well.


I would braze a new tooth on. Or I might even consider JB Weld, but you would have to wait for it to cure really long time before using it.
I find JB Weld really takes a while to cure... not the day that they say. Longer the better. You can machine it in a day, or hand cut the tooth.


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## Brento (Apr 11, 2022)

I can look and see how bad it is and see what i can do with the braze tmr. Ive never used it.


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## Brento (Apr 11, 2022)

I am also at the location to do my gearbox as well but question is do i want to tackle that as well right now. I know i have a customer sending me stuff to quote for work so i have to figure out what i want to do.


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## Brento (Apr 13, 2022)

Stupid question but if i need to add a shim for the headstock do i cut the shim to the shape of the other shims or do i just make a little rectangular piece to fit in. I am ordering some shimstock tonight. Tmr i will put the spindle in and check what i have and if i need any shimstock. I have the felt soaking tonight.


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## Brento (Apr 16, 2022)

Ive got everything back together minus the back gear. No overheating so that is fixed. I notice i have a little hard spot when i free hand the spindle. Always at the same spot. If i disengage the bull gear and move the spindle cone pulley it is free so it is on the right side. I did the bearing test and the bull gear side was at the .002 mark.


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## Brento (Apr 16, 2022)

Found the culprit. I added needle bearings to the back of the take up collar instead of the fiber washer. Some have said it helps with the radial movement. Well that collar now sticks out a touch farther then normal and engages with the reverse gear casting. I took that off and filed some material off and it is good to go. Now to set up my 4 Jaw and cut my back gear off for the ebay replacement. I think im gonna go with freezing the back gear assembly and heating up the gear and place it on. I was thinking a .0015 or so should be enough for that fit?


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## Jim F (Apr 16, 2022)

Brento said:


> Found the culprit. I added needle bearings to the back of the take up collar instead of the fiber washer. Some have said it helps with the radial movement. Well that collar now sticks out a touch farther then normal and engages with the reverse gear casting. I took that off and filed some material off and it is good to go. Now to set up my 4 Jaw and cut my back gear off for the ebay replacement. I think im gonna go with freezing the back gear assembly and heating up the gear and place it on. I was thinking a .0015 or so should be enough for that fit?


Let me know what you think of the Kit, I am considering it.


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## Brento (Apr 16, 2022)

Idr what i had before but I tightened up the take up collar pretty good and it still moves pretty good


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## hudstr (Apr 18, 2022)

Even if you overshoot the press fit you can save it with loctite 680 or similar product. I used it for my countershaft pulley and its been fine for over a year so far.


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## Brento (Apr 18, 2022)

That was my thought. Like i said i think .0015-.002 should be efficient for a press fit with freezing it.


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## Brento (May 22, 2022)

Well it has been a little while to get back to finish the lathe. Been a little crazy here. I froze the back gear assembly for a week by the time i got to it (woops). I set it up in the press and i heated up the gear and it slipped on most of the way leaving maybe 50 thou to push on. All in all i like the back gear fix. I decided the light press fit was the way to go but if it fails i can go back and do the loctite if need be. At this point my headstock has been fully redone and ready to make some chips. Now to do damage control in my shop since i left the garage door open for 30 minutes and everything sweat like crazy.


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