Jacobs Chuck Tapers

[wildo]

I have a Jacobs Super Chuck No. 11N. The chuck is stamped on three sides with:
"Heavy Duty Ball Bearing Jacobs Super Chuck"
"No. 11N Cap 0-3/8"
"Made in the USA"

When I google the No. 11N I seem to be finding 2JT as well as MT2 tapers. How do I determine what size taper this chuck has? Is it stamped on there somewhere? Do I just need to measure the drill press spindle that it came off of instead?

Also- Assuming it is a 2JT, is it possible to get a 5/8" capacity chuck with a 2JT taper? I seem to only find up to 1/2" capacity in 2JT.

 

[Bob Korves]

Does your drill press spindle have a male or female taper? What taper is it? There may be an adapter that is removable...

 

[wildo]

Ok- doing some research (sorry, I should have done that prior to starting the thread) on beautiful iron, I found that my drill is a JT type because the arbor is turned on the end of the spindle itself. The spindle does not have a female MT taper. Ok- so the chuck is definitely a JT type. Now I just need to determine if it's a 2JT or 3JT. I assume this can be determined by measuring the taper opening in the chuck: .5590" for 2JT, .5488 for 2JT Short, or .8110 for 3JT according to LMS. I already know the drill press has a 5/8" spindle and therefore I know it's not a 3JT. Now I just need to measure for the two 2JT options.

[EDIT]- Looks like it could also be a 33JT as well. Again- I'll just have to measure.

Thanks Bob for getting me thinking along the right lines...

 

[Bob Korves]

OK, if the spindle is a male taper, then you are stuck finding a chuck that will fit the taper. No other options beyond building a new spindle. If the actual spindle diameter is 5/8", you should stay away from big chucks regardless. The drill press is not heavy enough for that kind of work. If you have heavier work to do, consider getting a heavier duty drill press...