Lathe/Mandrel Vibrations

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Rogersab1223

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Jun 22, 2011
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Alexandria, VA
Hey all -

I have a turncrafter commander 12" vs lathe, which I know isn't the pinnacle of quality.

That said, I've noticed recently that my mandrels seem to be "wobbling" which causes vibration while turning. When I'm turning a hard piece (like stabilized burl or acrylic), I get a high pitched whine when I apply the tool, which is I think a vibration issue as well. When I take them off the lathe, the mandrels seem to be true and my centers, after shimming the tailstock, are pretty close to lining up.

Any ideas or things I should look for (other than a new lathe!)?

Thanks,
Andy
 
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monophoto

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Mar 13, 2010
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Saratoga Springs, NY
Is it a morse taper mandrel? If so, check to make sure that the taper is clean, but the female portion in the lathe, and the male component on the mandrel.

Try turning at a different speed. Also, try moving the tool rest closer to the workpiece.
 

DurocShark

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Jul 26, 2008
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Anaheim, CA
I found that I get better accuracy by mounting the mandrel as follows:

Place mandrel in headstock just far enough to keep it from falling out. Bring tailstock up, lock the base, and use your hand to hold the mandrel to the live center. Use the tailstock wheel to drive the mandrel into the headstock.

That gets everything lined up for me. Especially since replacing the pulleys and aligning the belt on my old Delta with a reeves drive, my lathe is rock solid now.
 

NewLondon88

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May 15, 2008
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Claremont NH
Is it a morse taper mandrel? If so, check to make sure that the taper is clean, but the female portion in the lathe, and the male component on the mandrel.

Do you have one of these? It will clean out the taper.
 

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JimB

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Mar 18, 2008
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West Henrietta, NY, USA.
To me it sounds like 2 different problems.

The mandrel is either bent (roll it on a flat surface such as glass), not seated correctly, too much preassure on the tailstock etc.

A high pitch whining is usually something slipping that shouldn't. You would get this becuase you are turning harder material and getting more resistence. I have gotten this from the lathe belt needing to be tightened slipping on pully) or the nurl nut on the mandrel needing to be tightened (blank and mandrel spinning at different speeds).
 

Fred

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Feb 18, 2007
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N.E. Atlanta, Georgia U.S.A.
Clean the MT on both the head and tail stock. I use a bottle bruch I got at a wine makers supply store. I clean both the lathe and the mandrel and apply a light coat of WD-40 and wipe then down.

To much pressure from the taildtock can and will cause bending of the mandrel.

Squeeling from the tool - sharpen it to restore a clean and sharp cutting edge.
 

Chthulhu

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Oct 15, 2010
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Location
Escondido, California
When joining precision-tapered tooling that is not held in place by a drawbar, the recommended method is to "wring" them together: after making sure the bore and the part going into it are clean, dry, and free of dings or burrs, bring the two together until they're about 1/2 inch from seated, then quickly twist and push at the same time. If the tapers are good and you've done this correctly, it will take a significant effort to get them apart again.
 

NewLondon88

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May 15, 2008
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I forget where I got mine, might have been Little Machine Shop or someone
like that. I think it was around $10 or less.
 
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