Internal thread cutting for threaded spindle

[Froneck]

I have a large Cincinnati dividing head (13") with threaded spindle 2.500 X 6TPI. Needing an arbor to cut slots in 11.5" OD plate with 1.250" ID. I made it using half hard 4140 from McMaster, spindle taper is B&S 11. Now just to have it I would like to thread a back plate for a chuck to mount on the spindle. Any simple way to do it? Not new to threading I do quite a bit of single point threading on a lathe and have both Hendey and P&W lathes with lead screw reverse and clock.

 

[SIP6A]

Take your dividing head apart and use the spindle as a gage.

 

[johnoder]

Take your dividing head apart and use the spindle as a gage.

Which just may be less time and effort than making a gage using dimensions of your threaded nose - a duplicate if you will

It will be smart to make it to FIT rather than to "book" dimensions of 2 1/2 - 6.

 

[Froneck]

Thanks guys! Guess I take the head apart! The actual spindle will be better than any gauge I make and probably less time.

 

[ramsay1]

Spindle Threading For Dividing Head

Hello: If you can bolt your blank to the spindle attachment on your lathe with a spacer between the two for a place for your boring bar threading tool to fall into, you may be able to remove the whole thing from your lathe for a try and put it back in the exact same place if you need to take another chip...

I have done this with a dog driver screwed onto my lathe spindle with the blank bolted to it with a large bearing race between the two....Usually I did it to fit the new piece to the lathe spindle I was using but I would think you could to it for another spindle.. I think I have done this from one lathe to another before if I remember right....

I suppose as with a lathe, it is better to finish the part on the spindle on which it will run..

Might not be practical for you but it was for me.. Cheers! Ramsay 1

 

[SIP6A]

I have also unscrewed the chuck from the lathe with the part I was threading on it and tried it on the mating part. Works quite well.