Jacobs 16N - thread mount?

If your going to use it in a drill press with a morse taper spindle, you could make a MT arbour with the custom diamitor to press fit/loctite into the hole in the chuck. (if it's centered and not off )
 
I made a new arbor, straight shank. I pressed it in with some Loctite after heating the drill chuck body with a heat gun to about 250-300. I used a +.002 interference fit.

Let it cool, and it seems pretty tight.

I put it into the lathe, and put an indicator on the chuck body, and got it to run to within .0005 of perfectly true. Then I center drilled (#3) the arbor end, and put in a live center for support.

Oddly, I couldn't keep the chuck body true when the live center was in place - I was off by .002-.003. I took a few cuts, just to get the arbor CLOSE to concentric with the chuck body.

Any idea what I may be doing wrong? or is introducing a few .001 when using a live center considered normal?

I have enough length on the arbor that I can face it off and try again, but I wanted to get some ideas here first.

-Tom
 
tcweb said:
I made a new arbor, straight shank. I pressed it in with some Loctite after heating the drill chuck body with a heat gun to about 250-300. I used a +.002 interference fit.

Let it cool, and it seems pretty tight.

I put it into the lathe, and put an indicator on the chuck body, and got it to run to within .0005 of perfectly true. Then I center drilled (#3) the arbor end, and put in a live center for support.

Oddly, I couldn't keep the chuck body true when the live center was in place - I was off by .002-.003. I took a few cuts, just to get the arbor CLOSE to concentric with the chuck body.

Any idea what I may be doing wrong? or is introducing a few .001 when using a live center considered normal?

I have enough length on the arbor that I can face it off and try again, but I wanted to get some ideas here first.

-Tom
Click to expand...
Any chance for a picture on how you're holding it? Need to see it in the lathe chuck.
Me personally, I heat the chuck in the toaster oven and freeze the arbor.
The tool maker that I learned some things from years ago did it that way. We had a heat treat oven in the tool room but the only freezer was over in the main office, and I was the 'step-n-fetch it' kid. Probably the only reason I even remember it.
We were putting together a half dozen new Super Chucks for the general machine shop.
 
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