jacobs chuck question

I have a Jacobs chuck that is marked NO-14, it is a 1/2 inch capacity ball bearing type with a # 2 morse taper . I would like to change it to a # 3 morse taper, but I am unsure if this has a changeable arbor. Does anyone have any info on this thing? I tried e-mailing Jacobs from the link on their site, but it was returned "undeliverable" I tried a Google search, and results for 14n only . thanks

The chuck has a female Jacobs taper and the 2MT arbor will be extremely difficult to remove. If you can get it out, you can then install a 3MT arbor. There are lots of ideas that have been discussed online about removing chuck arbors, so I will not repeat them.

An easy solution is to use a 3MT to 2MT reducing sleeve.

Larry

What Larry said. A sleeve is a lot cheaper and easier. I have about five different chucks and can use the tiniest of them in my L&S #4 tailstock or my radial drill by just sleeving.

Sometimes the arbors come out without too much trouble using the proper wedges, but yes, I’ve cut a few off and carefully bored out the JT until it got thin enough to bend what’s left of the arbor into the hole, grab and twist it out.


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Todd,
The 14N is the current model from Jacobs and has the 3JT(Jacobs Taper) mount. If your chuck is just a No.14 then it is quite a few years older but it may still have the same 3JT mount. The older 14N was a ball bearing 'Super Chuck' also with the 3JT mount but had a filling slot for the bearings when reassembled rather than bearings embedded within a plastic ring.
The wedges for arbor removal are only going to work if there is a shoulder on the arbor. Typical Jacobs arbor install on a chuck body leaves a small shoulder. Then the two wedges slide together and press against the shoulder of the arbor and the base of the chuck.
I would squeeze the wedges together via a large vise. The chuck can be disassembled, then apply some heat near the base. Otherwise Jacobs instructions say a hole can be drilled from the jaw side so the old arbor can be tapped out.
Look for replacement arbors on Ebay.
The diameter of the arbor that is outside the mount of the chuck is about 0.812 for a 3JT.
The large diameter of the 3JT on a 14N is about 0.797
John

ok so now I know that the arbor is a removable one on this chuck. I tried drilling through the body as the Jacobs site says but it seems to be very hard. I installed it in a jig in my drill press, and had at it with a colbalt bit but it did not touch it. Any advise ?

todd1163 said:

...Any advise ?

Click to expand...

Get the reducing sleeve. It is simple and cheap if your chuck and arbor are in good condition.

If you drill a hole in the chuck, you will also get to learn how to disassemble a chuck to clean it. I have drilled through the inside of Jacobs chucks to allow using a dowel pin and 12 ton press to remove a bad arbor. The chuck bodies were soft enough to drill with ordinary HS bits.

I suspect you will have trouble finding a rebuild kit for the old model chuck, which post #5 suggested has different bearings. You will not like the price of the rebuild kit for the current model chuck, if it does work. Keep in mind that Jacobs is now a brand name applied to products made in China. Jacobs(R) 14N (#3221) Ball Bearing Super Chuck Service Kit
| Fastenal https://www.industrialhardware.com/...der-models-jacobs-chuck-33418d-9a-33418d.html

If you can't deal with the simple and cheap solution, then go with the simple and expensive solution and get a chuck that has a 3MT arbor.

Larry