13'', .030 off after a move

hi guys, picked up this lathe last december. was my first. learned quite a bit on it, making mostly motorcycle parts.(forward controls, spacers, bungs, etc.. we moved a few months ago, had the lathe broken down to pieces, re assembled it in the new garage, and now the chuck is spinning .030 off center. The main shaft is spinning true, pullys are spinning true, just the chuck is off. i tried loosening the 3 bolts holding the chuck on and moving it around using and indicator and still .030 is the BEST i can get. Any thoughts here?? i need to start using it again soon for a bike build. Might just be ordering a new jaw and backplate...

If everything else is OK and survived the move, then the problem might be some chips floating around in the chuck that are affecting the jaw threads. See if you can clean it out, and lube it.

Remove the chuck from its back plate. Does the back plate run true? If not, inspect the spindle and the backplate mating surfaces carefully.

allan

Also look in the threads of the backplate, chips can lodge in there and cause problems. A hook scriber or similar tool can fish them out.

kitno455 said:

Remove the chuck from its back plate. Does the back plate run true? If not, inspect the spindle and the backplate mating surfaces carefully.

allan

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+1
And clean the threads, both spindle and chuck backing plate. It doesn't take much of a chip in the threads to throw thing off.

Any chance you removed the chuck jaws and put them back in the wrong spot? Last time I had significant, mysterious, runout that's what it was.

Cole2534 said:

Any chance you removed the chuck jaws and put them back in the wrong spot? Last time I had significant, mysterious, runout that's what it was.

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Misplaced jaws would be much more than the 0.030" run out he's seeing.

I'm assuming that you've properly levelled the lathe in it's new location?

Brian

Sachmanram said:

I'm assuming that you've properly levelled the lathe in it's new location?

Brian

Click to expand...

How would levelling affect chuck run out?

Rotated the chuck one screw hole and with some whacking got it within .010. Gonna mess with it some more tomorrow night. Spindle and backing plate are dead on.

Just as a general point to follow while stripping and cleaning chucks that far too many people don't know. Other than I guess the bottom of the barrel dirt cheap chucks, they all get assembled and then the jaws get precision ground in their working positions. So it's important that everything gets marked and returned to the same position it was originally in. The pinions that move the jaws are especially important. I usually just use some masking tape to assign a number on the chuck and each part so they go back into the same position. This is what Bison recommends, and I'd guess all the other good chuck producers would do so also. Since there's no way to know if that's been done with a second hand chuck, if your getting fairly low run out then I'd still do this. If the chuck and back plate aren't match marked, then it's still important that they go back togeather in the same position they came apart.

Pete