View Full Version : Did they ever make a JT3 ot JT4 adapter

01-24-2010, 07:04 PM
I have 2 Jacobs 19N 3/4 chucks, both have JT4, my drill press has JT3 in the
spindle and it ain't coming out so I am stuck with a JT3 spindle. This is a large
20" swing HF production drill press and I want to use the big chuck on it.
Does anyone know if they ever made a JT3 to JT4 adapter?

01-24-2010, 09:55 PM
Short answer, no, they do not make JT adaptors.

01-24-2010, 09:59 PM
Yes they do make MT adapters assuming you meant Morse taper,KBC and the other usual suspects have them-

http://www.kbctools.com/USA/Main.cfm item# 1-5161-045 $22.80

BUT,it would be better if you can replace the arbors since the extension sockets eat up daylight under the quill.Can you see the end of the shanks looking in the chuck?

01-24-2010, 10:05 PM
If you can't get the MT/JT arbor out of the spindle, why not remove the spindle and machine it out? It seems it would make the machine a lot more useful to you. Does the machine not have the removal slot in the quill for the MT arbor? Did it get put together w/ locktight or something? Most of the time, you can get them out, but you might have to get creative...

01-24-2010, 10:53 PM
Tried a drift tool with a hammer, then took the spindle out and put on my arbor
press. Still couldn't the drift tool to push the arbor out so I just gave up on the idea of removing it.

01-24-2010, 11:14 PM
Tap the drift in til it sticks and warm the spindle up with a heat gun.It may take 15-20 minutes of heat to warm the spindle and housing up,but usually it will expand the bore enough for the arbor to loosen up.

Ian B
01-25-2010, 04:53 AM
Getting the existing arbour out and replacing it with a JT4 arbour is the best solution.

Not all drill drifts are the same - some have fairly steep tapers - maybe find or make one with a shallower taper. Heating the spindle's a good idea too.

If it *really* won't come out, then making a JT3 to JT4 adaptor should be possible - it's just a short sleeve tapered inside and out. Wall thickness would be about 0.16", which is manageable.

0 .25000" .22844 .43750
1 .38400 .33341 .65625
2 .55900 .48764 .87500
2 short .54880 .48764 .75000
3 .81100 .74610 1.21875
4 1.12400 1.03720 1.65625
5 1.41300 1.31611 1.87500
6 .67600 .62409 1.00000
33 .62401 .56051 1.00000


01-25-2010, 07:36 AM
I wonder if rust got in there. That allways makes em stick real good, usally seems to form after awhile of non use -_-;

01-25-2010, 09:13 AM
This was a new HF 20" swing production drill press that had been dropped before it was sold, on the head not the spindle. I purchased it and tried to repair some small problems. I didn't get the chuck, motor or table crank gear/handle. I was going to replace the chuck with a better one anyway, everythings done but the chuck. I having 2 - Jacobs 18N super chucks not in use so I really need to get one fitted to the drill press.