Jacobs 16N - thread mount?

[tcweb]

I just picked up a Jacobs 16N super chuck, with some superficial surface rust and what appear to be completely unused jaws. (which is what caught my attention on the flea bay listing)

Chuck arrived looks great. But upon flipping it over, I see what looks like a 1/2" fine thread going into the body of the chuck!
I've never seen a super chuck with a thread mount. I'm wondering if someone cut off the JT3 arbor, and drilled/tapped it.

Any thoughts? I can post pics if it helps. this is a "made in USA" super chuck, not one of the china made jacobs.

-Tom

 

[Nogoingback]

I have an old Jacobs catalog which shows lots of threaded plain bearing chucks, but the 16N is shown as having 3JT mount only.
Of course that doesn't mean Jacobs didn't make them that way.

 

[benmychree]

The threaded mounts were generally made for power tool use, but there is no reason that they could not be used on a machine if the arbor was carefully centered and threaded.

 

[tcweb]

Here are the pics...

 

[darkzero]

That looks like part of a Jacobs taper arbor that has been cut off & threaded. I have never seen any size Jacobs Super Ball Bearing chuck come with a threaded mount.

 

[darkzero]

If that is a cut off arbor, you can make a sleeve, ID big enough so that piece of arbor can fit through, place it on the body, then use a washer & a bolt to pull it out. Assuming that thread is common for a bolt size. If not you could easily whip something up.

If you're not sure what I'm mean (by my poor explanation ), I can take some pics, have a few BB chucks on my bench right now.

 

[Choiliefan]

I have one of these chucks with the threaded mount.
Not sure when/where I acquired it (Lockeed Burbank surplus yard perhaps) but I use it on an ancient Hisey-Wolf toolpost grinder which is used as a polishing lathe on the bench.
The thread of the chuck is fairly soft so it conformed to the threaded spindle on the Hisey with a bit of gentle persuasion and runs tue enough.
It's an excellent chuck and probably worthwhile making your own custom arbor for it.

 

[Choiliefan]

Thinking about it a bit more, these threaded chucks may have been OEM on some large hand drill or BUX-type magnetic?

 

[stupoty]

I just picked up a Jacobs 16N super chuck, with some superficial surface rust and what appear to be completely unused jaws. (which is what caught my attention on the flea bay listing)

Chuck arrived looks great. But upon flipping it over, I see what looks like a 1/2" fine thread going into the body of the chuck!
I've never seen a super chuck with a thread mount. I'm wondering if someone cut off the JT3 arbor, and drilled/tapped it.

Any thoughts? I can post pics if it helps. this is a "made in USA" super chuck, not one of the china made jacobs.

-Tom

A lot of hand drills have a threaded chuck mount, from memory the ones I have seen are course thread.

I have made a strait shank mandrill for one of them, works well.

Stu

 

[RobertB]

Give Jacobs a call 1-866-907-9716 their tech support guys are usually very helpful and should be able to tell you if the 16N was ever made with a thread mount.