# Vibration in Craftsman/Atlas 101 12x24 lathe



## JPMacG (Jul 9, 2014)

I have been chasing down a vibration issue on my Craftsman/Atlas 101 series 12x24 lathe.  I think the vibration is coming from the large 2-step pulley on the rear pulley assembly between the motor and the lathe spindle.  That pulley is bent slightly, so that it wiggles side to side by about 1/4 inch when turning.

I'm wondering what to do.  It seems my options are:
1) Try to bend it straight, which may be successful but could make it worse.
2) Buy a used replacement Atlas pulley on ebay for around $60, which may or may not be better than what I have now.
3) Go to a variable frequency drive, and belt the motor directly to the spindle, removing the entire intermediate pulley assembly.  

I'm not sure that 3) is even feasible, but it would be a neat solution if possible.

I welcome any thoughts or suggestions!


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## caveBob (Jul 9, 2014)

I would skip #1 (forget about straightening the pulley, might be possible but I wouldn't fuss with it.) You could make a pulley, someone here did that recently if I remember correctly. One of these days I'll make my own too because there is a little wobble in mine too. I'm keeping the pulleys even though I run a DC vari speed motor... really like the usable torque range with this setup.

2cents...


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## 12bolts (Jul 9, 2014)

If the pulley hole is slightly larger than the shaft it may be cocking over to one side, especially if it is retained by 1 screw. Maybe just needs a shim to square it up on the shaft.

Cheers Phil


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## JPMacG (Jul 9, 2014)

Thanks.   I will check out the fit of the pulley on the shaft.  That is a good thought.  I also like the idea of the variable speed DC motor.  I'll look into that as well.

The whole lathe vibrates noticeably, yet I am getting a nice surface finish and a run out of less than 0.001 inch on a 1.2 inch diameter, so I guess I should be happy.


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## VSAncona (Jul 10, 2014)

The VFD would be a great option.

The last time I checked, Clausing still stocked the two-step pulley. They aren't cheap, but the new ones are much more rigid than the original spoked design on the older lathes. So that's another possibility.


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## EOD1959 (Jul 10, 2014)

Had the same problem with my 101 12x32 Atlas/Craftsman.I made a new jack shaft & bushings, problem gone, no wobble no vibration!!!


Dennis















Atlas/


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## pdentrem (Jul 10, 2014)

If you find the pulley shaft hole is belled or oversize, square up the pulley and bore a new and properly aligned oversized hole and use a bushing to fit to the countershaft. 

The original spoked pulley was very brittle after a time. You will not likely be able to bent/push the pulley back into alignment to the shaft. It will crack the spokes. 

Another way would be cut out the hub and spokes and make a new center to mount the pulley onto. If you did this, you might as well make it all the way.
Pierre


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## mattygee (Jul 11, 2014)

I went with a 3 phase/variable speed setup with a 2 step pulley on the motor and a sliding mount that allow me to use all 3 belt sheaves on the spindle pulley.  It works well, and I can reverse the motor which comes in handy when backing up the carriage without disengaging the 1/2 nuts.  I can shoot you a pic if you'd like.


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## JPMacG (Jul 11, 2014)

Yes, I would very much like to see a photo.   Thanks!   Are you sliding the motor in order to stay with the 2-step motor pulley that came with the lathe?

I tried to remove the large 2-step pulley last night.   I would need a puller to get it off.   It is definitely not a sloppy fit.


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## pdentrem (Jul 11, 2014)

Likely dried out grease and grime plus that pesky setscrew indentation on the shaft is holding things on!
Pierre


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## JOEZ (Jul 11, 2014)

Have you checked the runout on the motor shaft?


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## kd4gij (Jul 11, 2014)

Don't try to use a puller on it it will break. loosen every thing on that shaft and tap it through the pulley. That is how I get mine off. I am all for a 3 phase motor and a vfd, but I would not get rid of any of the drive train. If your pulley is warped Clausing sales a updated one for about $92.00 shipped.


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## wa5cab (Jul 12, 2014)

JPMacG,

The reasons for not getting rid of all (or any) of the stepped pulleys if you change the motor to one of the several kinds of variable speed ones are threefold.  One is that the useful delta-RPM range of the variable speed motor is probably going to be less than the range of the 8-step pulley system.  Two is that most variable speed motors have a torque capability proportional to the RPM and the low end torque may be inadequate (and if you go to a much higher HP motor to offset this you may cause other problems).  The third is that the cooling fan normally runs at motor RPM and the motor will probably overheat at low RPM.  

Going to a 4-step motor pulley would probably be a workable solution but the step farthest from the motor is a long way from the bearing and you might bend the motor shaft.  Plus if you eliminate the countershaft, you'll have to not only find a motor pulley with the right ratio between steps but will also have to invent an easy to use belt tensioning mechanism.  Because if it isn't easy to use, the human tendency will be to run the motor too slow rather than fight with a hard to use belt tensioner in order to change pulley steps.  

Robert D.


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## JPMacG (Jul 12, 2014)

Thank you everyone!  As usual, the information that I receive on this forum has been amazing.   I won't have time to work on the lathe for the next several days, so I will just think it over.   Right now I am thinking I will check the shaft runout and pulley fit and rework or replace one or both as necessary.


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## mattygee (Jul 15, 2014)

JPMacG said:


> Yes, I would very much like to see a photo.   Thanks!   Are you sliding the motor in order to stay with the 2-step motor pulley that came with the lathe?
> 
> I tried to remove the large 2-step pulley last night.   I would need a puller to get it off.   It is definitely not a sloppy fit.



Sorry for the slow response... Busy around here lately...  As you can see in the pics, the motor base is the original one from the countershaft assembly.  The VFD is housed in a box along with a cooling fan and 12 volt power supply.  I need to trim the cutout a little better and add a piece of Plexiglas over it.  There are a few tweaks I need to make but its worked well so far.


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## timmeh (Aug 29, 2014)

if the pulley is bent, rather than try to staighten it, dial up to the outer then bore and face the hub, make a bush to suit. hold on at the hub, assuming you have 4jaw and another lathe or know someone who has.


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