View Full Version : Looking for odd Jacobs Chuck Key

07-12-2006, 11:07 AM
Some time ago I got an *old* Jacobs Super Chuck. I don't recall the patent date, but it is rather old and also says Jacobs Spiral Gear Chuck around the body. It has a knurled body rather than the vertical groves that are on the current models. You can see it in the picture below.


In any case, I am trying to find a key for it. It is unique in that the teeth on the chuck genuinely do have some spiral to their cut and a standard key will not work.

I had initially relegated it to use on the lathe where I could make use of a little tommy bar and the knurling to hand tighten it adequately. I now have another use for it and would love to find the key that goes with it. The only way to not damage drill bits or the chuck for that matter is to get things tight...and that takes a key. I had thought about making a knurled ring of sorts that would pin into the key holes and treating it as a keyless chuck, but my experience with the tommy bar tightening method makes it clear why keyless chucks are designed a little differently.

Anyone out there seen what I need?


07-12-2006, 11:17 AM
I see those chucks occasionally, I have one of the smaller ones. It has a patent date of 1925, and I think it is one of the first Super Chucks. I don't think the spiral gear lasted long.

I have never found a key for one though. You might want to sell it as an antique on eBay and use the funds to buy a newer version.

I would guess that the spiral threads were an advantage in tightening, but would make opening the now tight chuck problematical.

07-12-2006, 11:48 AM
It might be an interesting challenge to try to make a mating chuck key. Undoubtedly more trouble than it would be worth, except for the bragging rights that you did it.

07-12-2006, 12:12 PM
I have several old chuck keys, but none with a spiral pitch. Any idea of the Jacobs 'K' number for the key?
John Burchett
in Byng OK

J Tiers
07-12-2006, 12:35 PM
I think the spiral gear idea is really good...... for tightening, et least.....

The tighter you turn, the better the key holds in.

Now, when you go to LOOSEN it, there might be some trouble.......... ;) :eek:

07-12-2006, 01:31 PM
I too have several old Jacobs chucks. A knurled No.3 with a patent date of 1902 and a couple of the early Super Chucks. I've never seen a Jacobs with the helix gear sleeve. I'd be willing to bet it was a new (1925) trial version that didn't go over too big for just the reasons mentioned--Loosening a tight grip. It was probably discontinued. It must be rare! Besides making a new key, I don't see many options unless you replace the gear sleeve.


07-12-2006, 01:36 PM
After looking at your picture again, it's not loosening that would be a problem. It would be tightening! :eek: It looks like the key would ride up when tightening. Loosening wouldn't be a problem.

07-12-2006, 01:48 PM
Don't think so. It should pull the key in when tightening and push it out when loosening. Tightening you rotate the outer sleeve counter clockwise as viewed from the user end (not bit end) of the chuck.

07-12-2006, 01:52 PM
Look again. Turning The KEY clockwise tightens, counter-clockwise loosens. The sleeve turns opposite when viewed from the user end. ;)

07-12-2006, 02:03 PM
That's right. Therefore the teeth in the key will tend to slide toward the center forcing the key into the chuck when tightening.

john hobdeclipe
07-12-2006, 02:06 PM
The way I see it, the key will tend to push out and disengage when tightening, and pull in when loosening. Perhaps this was an attempt to prevent overtightening?

07-12-2006, 02:13 PM
It should pull in when tightening.


07-12-2006, 02:15 PM
Oh boy! Here we go. :D

I still say it's a bad design. :D

The PM guys are going to be laughing over this argument.

07-12-2006, 02:40 PM
Here's a head on view of the chuck. The sleeve is turned clockwise to tighten. Note in the previous photo, the gear also has a buttress shape.


Aside from either being difficult to tighten or loosen depending on personal preference, it was certainly more expensive to manufacture.

It was probably the brainchild of the 1925 equivalent of the pointy haired boss.

07-12-2006, 02:49 PM
Toward the end of his career he moved to Coca Cola where he developed the idea of New Coke.

07-12-2006, 03:20 PM
JC-- where'd you get that amazing technology that lets you rotate an object in a picture:) I am guessing you have one too and that is a picture of yours.

I do suppose that camming out might be an issue when loosening the chuck, and that may be a reason for the demise of the design, but I tend to think that it probably had more to do with the costs of production than anything else. It should tend to "cam in" when tightening....if only it could work in your favor both ways.

I don' t know the key number and it may be worth a call to Jacobs to see what they can tell me. I would be darned surprised if they have the right key in stock for what clearly looks like an old design.


07-12-2006, 03:53 PM
I think I saw one of those chuck keys not long ago at a flea market. I just remember the odd shaped teeth that fit no chuck I had ever seen. If it's not for that chuck, it was for a chuck like it. I bought a like new Jacobs J4 key from the fellow for $2-3 IIRC and the odd ball was probably the same price and though it had some serious "patina", it was usable I think...

john hobdeclipe
07-12-2006, 04:49 PM
Ah, I see it now...Yes, it will pull in when tightening and cam out when loosening. So I stand corrected from my previous post.

Perhaps an effort to prevent over-loosening? :D

George Hodge
07-12-2006, 10:32 PM
I have the same chuck,in great condition,probably cause the original owner lost the key and got another chuck.Called the Jacobs phone number and the nice lady said they never made such an animal. Mine's patented in 1901. I have another Jacobs chuck,same size,with knurled outer shell,with straight teeth.

07-12-2006, 10:40 PM
All the ones I have seen have also been in very good condition as well as missing the key. The previous owners probably threw their key at Sir John's neighbor's cat after having it cam out while trying to loosen it.

03-05-2015, 10:18 AM
Yes, I know it's a 9 year old thread! A Google search on the spiral gear concept lead me here. I've had, and used, one of these chucks (with the matching key) for years and always wondered about the marketing and logic behind it. Interesting to see the arguments and speculation as to why it was dropped. It does indeed make for more secure tightening but requires an extra hard push inwards to release it without having the teeth disengage. I no longer use it so I put it on eBay to see if anyone considers it a collectible?

03-05-2015, 03:05 PM
I have one with the knurled OD but with straight teeth on the outside. It has 3 patent dates on it, the earliest being 1902.


03-18-2019, 02:36 PM
Hey, I found one on fleabay with a key for once. Check it out. I know it's an old thread but I figured I'd put this here just for information's sake.