Drill chuck taper.

I have a half inch Jacob's chuck that mounts on a 5/8" shaft with a #2 morse taper. The morse taper is way too large for the #2 receiver on my little lathe.
This was used on an old Blount wood lathe that was mounted on a 12" engine lathe chassis. The #2 Morse tapers for that tail stock was pretty big. I would like to find a #2 taper that fits my little Jet lathe and has a 5/8" extension for the drill chuck to attach to. It is held by a set screw. I have checked McMaster-Carr, and Enco and they don't appear to have such an animal. Any suggestions where I might find one?

Don it sounds like the hole in your tailstock is a smaller taper size than your shank. If you measure the hole in your tailstock at the big end with a stick rule, the approximate diameter and corresponding morse taper number would be as follows

#1 MT ~1/2"
#2 MT ~11/16"
#3 MT ~15/16"

These numbers aren't exact, but there's enough difference from one to the next that its easy enough to determine which female taper your tailstock has from this measurement.

The set screw sounds odd to me. Is is a straight shank on the chuck end and set screw in the chuck?

Don, If you have a means of posting a pic that might help. Both the current arbor and one that fits your Jet.

Most Jacobs chucks have a Jacobs Taper (JT) mount; say a JT#2 into the chuck. This is a short taper. Others have a threaded mount. I've never seen a Jacobs arbor and chuck that actually had a 5/8" cylinder going into the chuck body. A JT arbor is so short you might easily mistake it for a cylinder?

My guess is that you have a chuck with a JT2 taper into the chuck and a MT (Morse) #2 taper for the tailstock (that's pretty standard for med-small wood and metal lathes). If it came off a wood lathe, you may have a threaded ID into the back of a MT2 arbor to use with a drawbolt through the headstock.

Have no idea what your Jet uses, but it might possibly be a shortened MT 2. If that's the case, rather than cut up your current arbor, buy a cheap one and cut it down in length.

Oops, forgot about another possibility. You may have a Jacobs chuck originally intended for use on a ShopSmith? That WOULD have a 5/8" female socket and a setscrew. The pix will help us.

Trying to post a pic, but can't make it work. The link looks like the one in the instructions and the preview says there is a picture but it doesn't show. Any clue to what I am doing wrong? I've used html before but not UBB.

BINGO!!!!! Pete. I had forgotten where I got the thing. The chuck did come with an early Shopsmith i bought in the fifties in Seattle. A friend with an engine lathe turned the taper for me so I could se it on the old Blount wood lathe. He turned it a little small so he nurled it to make it fit. All the centers which came with the lathe had the odd size taper. Way too small to be a #3, but larger than a normal #2. On the pic you can see how much larger the big end of the taper is than the 5/3" shaft for the chuck.

That should be 5/8"

Hi Don, Yep, that's for a ShopSmith. Instead of trying to adapt this to your Jet, I'd suggest getting a new (maybe $25 for a good import) or used (even cheaper for a nice Jacobs) chuck with a (#2 Morse?) taper to fit your tailstock.

The ShopSmith chuck will have value for others in a trade, but it probably will be off several thousands, in addition to the usual runout, due to the setscrew holding arrangement.