New chuck, adapter is too short.

Mauser lover

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I got a new (to me) chuck with adapter for my lathe, but the adapter is too short for my spindle. Does anyone use a washer (for lack of a better word) against the shoulder at the back of the spindle to push the chuck/adapter assembly forward? I just need to buy 1/8 inch or perhaps a shade more.

My other idea would be to shave a wee bit off the back of the chuck to make it fit.

Or I could get another adapter.

Good idea? Bad idea? Anyone else do it? I haven't found anyone recommending it, so I don't know if that means it is a bad idea, or if it isn't a regularly encountered problem, or if everyone does it and just doesn't mention it!

Thanks!
 
What type of spindle? I'm not quite following, why do you need it to push out forward? Would it affect the register mating surfaces? I wouldn't do it for a permanent solution, maybe if you needed it in a pinch. The spindle is a precision part of the lathe, introducing something like this just may add more error & loose rigidity. I would get the proper adapter or make a new one.
 
Hmm, that's not a great solution. You really need that register between the backing plate and spindle, threads themselves (I'm assuming your spindle is threaded) do not make for good alignment. Putting a 1/8" washer in there might reduce the depth of that register contact enough to be ineffective. You would also want a precision ground washer -- harware store variety are far from accurate and would likely introduce considerable runout on the chuck face.

Have you verified that there is enough thread inside the backing plate to fully accept the spindle nose? Sometimes they are not threaded all the way through, so what looks like being too short can really be lack of threads. If that were the case, either continuing the threads through or cutting a relief where the threads fall short might allow the neck to thread on fully. I'm not sure how "shaving a wee bit off the back the chuck" would get you where you want to be, unless you mean creating a recess in the chuck for the spindle nose to extend into?

I've made several assumptions here so if your situation is different you'll need to further clarify.

-frank
 
creating a recess in the chuck for the spindle nose to extend into

Yep. That.

This is not quite what I would think of as a "normal" chuck. It is definitely an older chuck. I'll try to remember to shoot a picture of it. The lathe does have a threaded spindle. And there is plenty of thread in the adapter. I do need to open up the diameter of the adapter so it will fit over the spindle, and was hoping that if I kept that close fitting it might help with the precision issue.
 
Two pictures of the back of the chuck, one picture of the spindle, and one picture of the adapter. It's certainly a very lightweight chuck. I hope it will do okay on this machine! Don't know of any other purpose for this chuck though, so I'm guessing it will be fine.

IMG_0916.JPGIMG_0917.JPGIMG_0918.JPGIMG_0919.JPG
 
It is held on by screws, and fits snugly inside a recess that locates it concentrically. Which is why I measured it wrong at the start. I measured from the back of the adapter to the lip of the recess, which is raised about 1/8 inch or a little more.
 
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