Help with a Jacobs Chuck

[Todd.Brock]

I am trying to figure out if there is a way to use this chuck with my Clausing drill press. It came with a box of extra parts. The third jaw is not show in the picture, however I do have it. I believe I have a JT33 per the instruction manual for my drill press vs a Morse Taper. Is there an adapter for this, or do I just need a new chuck? Is there any value in this existing chuck to offset the new one, or is that taper super obscure/obsolute, etc? I have a Rohm in mind as it is cost effective compared to a USA Jacobs.

This is the top of the chuck and an extra spindle in the box of parts.

This pic is of the sprindle with a collar from what I believe to be part of a JT33 chuck

This is the spindle without the adapter

This is the taper of the chuck

Made in the USA!

 

[RetiredOldGuy]

I do not believe that you can use that chuck.

My Powermatic variable speed floor model has the same spindle as your Clausing and has a dedicated Jacobs key type chuck. I would get the Rohm or look into a Albrecht keyless. I see them on Craigs list from time to time for not too much (I sold a couple of used ones a few years ago for cheap when I downsized my shop).

On my Powermatic I keep two chucks handy and switch between a 13mm keyless Albrecht and the 0 -1/12" keyed Jacobs for the larger bits.

Keep the threaded collar on the spindle if you can. It comes in handy for removing and replacing chucks.

mike

 

[Rusty Musket]

I picked up a whole box of chucks last night and have not even had a chance to look at them. If you see anything that looks like it could work for you let me know. -Rusty

 

[454ragtop]

Looks like a match to me. Neither the chuck nor your drill press spindle are Morse taper, think they're both Jacobs 33 taper. Put some Prussian Blue, or even magic marker, on the spindle taper and put the chuck on it and spin it it to see how the tapers match up.
HTH, Jim

 

[A_Pmech]

Todd,

I've never seen one of those style chuck mounts in person, but it looks like you have a Jacobs 33 taper spindle. The chuck is a also a Jacobs 33 taper. They should fit together.

The collar's only purpose in that application should be to press the chuck off the spindle. Be sure to reinstall and test it before seating the chuck, or you'll be drilling the chuck body and removing the spindle from the machine to press the spindle out of the chuck.

I think the Jacobs 633? had a collar that served to lock the chuck to the spindle with a threaded connection in addition to the taper friction. However, I think that collar stayed on the chuck...

 

[Provincial]

I have a Craftsman drill press from the 1970's that has a Jacobs #33 taper chuck with a collar. The manual states that the purpose of the collar is to retain the chuck on the taper when you use it as a router. Apparently, there is a vibration that tends to work the chuck loose on the taper.

I believe that the collar is most useful for the rest of us to help remove and replace the chuck. The original chuck key has a turned-down area on the end of the handle that fits the spanner wrench holes in the collar, which makes it an assembly tool.

P.S. The chuck is still available. It is Sears p/n 38623. Current price is $84.29. I don't think the chuck key is included. It is p/n 817339, priced at $18.80.

Jacobs lists a Model 34-33C which has the collar. It is a direct replacement for the old 633 chuck used by Craftsman and others. Comes with a key! And cheaper, too.

 

[larry_g]

http://www.practicalmachinist.com/vb/general/advice-wanted-jacobs-33-taper-205493/
Another thread on this subject.

lg
no neat sig line

 

[Todd.Brock]

Hey all, bringing this thread back b/c I still need some help! I bought a Rohm JT33. The taper fits, but there is no threaded collar. I thought that I was buying the correct part. Any thoughts here?

 

[zkling]

Hi Todd,
Can you post the model of your clausing drill press?

Most of those threaded collar chucks / tapers are 34-33C. Which is the chuck you had originally. Have you had it assembled or did it come in parts? It should fit that press.

You should be fine with just a 33 taper chuck under normal drill press operations (ex. NO side loading). Those old jacobs chucks are real nice though.

 

[454ragtop]

That new chuck should be fine. If you haven't installed it yet, might want to put the threaded collar on the spindle first, it will protect those threads and make future chuck removal easier.
Jim

 

[gatewaysysop]

That new chuck should be fine. If you haven't installed it yet, might want to put the threaded collar on the spindle first, it will protect those threads and make future chuck removal easier.
Jim

What you have should work fine, the collar attached to the chuck is optional. A collar separate from the chuck is useful for removing a chuck that has no integrated collar of its own.

 

[Todd.Brock]

Thanks everyone. I put it on an tapped it with a deadblow to lock it in. I will start drilling with it and call it good. Thanks again!

 

[justanengineer]

Thanks everyone. I put it on an tapped it with a deadblow to lock it in. I will start drilling with it and call it good. Thanks again!

Not to nitpick and its up to the individual, but Ive always been taught and have several texts that warn against using a mallet for seating tapers. Admittedly, I also know several machinists who have done so for decades and swear its an old wives tale, but I wont do it. Personally, I try to be super gentle with equipment and if the taper doesnt seat with hand pressure against it, I use a block of wood on the table and the press/tailstock/etc....as a press. I also do this with taper drills and other tooling as well.

 

[Todd.Brock]

I thought of that so I used the side of a rubber deadblow mallet with a couple taps upward from about 3 inches. I def was concerned about damaging the chuck and thought that was a safe way to accomplih. I figure the first time I drill there will be way more pressure than I ever put in it. I just didn't want it to fall off and hit the floor!!