Another Jacobs drill chuck thread

[dp]

Note: There's a question at bottom of post!

I took my Jacobs 14N apart again to see if it was worth buying repair parts for. I found what I needed at MSC. Last time I took it apart I was sure it was unsalvageable but this time round I noted something I missed last time.

The bearing races: The small one is a ring, nicely made, no rust or worn spots. The other one was broken in half. I didn't bother further, I put it back together and forgot about it.

Then I saw the repair parts thanks to the recent Jacobs chuck threads I've seen and what I saw was the larger race is split. On disassembling it the second time what I discovered is my race wasn't broken in a bad way, it was intentionally split by breaking it. It had to have been else there's no way it can even be installed, that lamp of brilliance being too dim for me to have noticed first time around.

So this time I carefully scrubbed and picked out all the crud, washed the balls, deburred it as needed, then greased it and assembled it. That cuss is now a fine, smooth acting chuck.

Here's the question:

The MT#2 taper is pretty battered and I'd like to replace it. I don't have any wedges so thought I'd ask if anyone has any clever way of getting the arbor out of the chuck. The chuck end of the arbor is a JT33, I believe. I think I'm going to have to buy some wedges.

[tiptop]

Dennis,

I have a set of wedges I could loan you, or they wouldn't be hard to make for a one time shot. Send me a PM if you want me to send them up for a day or two.

Jay

[rancherbill]

Take the arbor out of the quill with the chuck attached.

Look up into the chuck, if it's like mine you can see the arbor. Put the arbor and drill chuck on a bench and wrap with cloth. Stick a punch up into the chuck and give it a sharp, but, gentle tap. They will pop apart. Make sure they are wrapped up as you don't want to damage the arbor.

[dp]

Take the arbor out of the quill with the chuck attached.

Look up into the chuck, if it's like mine you can see the arbor. Put the arbor and drill chuck on a bench and wrap with cloth. Stick a punch up into the chuck and give it a sharp, but, gentle tap. They will pop apart. Make sure they are wrapped up as you don't want to damage the arbor.

That's what i thought, too, but it's not drilled through.

[Mark Hockett]

Dennis,
I have a set of wedges too. If you are coming over to Jons party on Saturday you could use them to remove the chuck, I live very close to Jon.

[rohart]

My 14N was drilled through, but I have an 18N - which is waiting for a machine big enough for it - and that wasn't. It was on an MT4 which was no good for me, so I drilled through. It wasn't a problem. It wasn't hardened up in there, and there was a machining pip that centered the drill. I took it gently, of course.

I'd like to ask if machining an arbor out of free cutting MS would be good enough, as I'm about giving up finding a genuine arbor for my 18N ?

[John Stevenson]

I was going to post the same as Richard, drill thru the chuck although I have had a couple of Metabo that were hardened.

Worse ones are the MT2's to JT6's as the tapers pretty well match and there is no lip for wedges and tapping thru is about the only way.

Plain steel does OK in a home shop, I made many of my own before imports came in, some are still in daily use.

.

[JCHannum]

The chuck body can be drilled through for removal. I usually drill with a tap size drill and tap with a fine thread, maybe 3/8-24 or so for a 14N, and use a socket head cap screw to push the arbor out. If that does not work, put as much pressure as possible on the screw and then smack it with a heavy hammer. There is usually enough play in the threads for that to cause the JT to give up. I find this method preferrable to chasing the chuck around the shop with a drift and hammer.

The wedges are available from most tool houses, and are reasonably priced, under $10.00 a set. If the arbor does not have a shoulder to work against, it can be drilled through close to the chuck body and a pin used in the hole for the wedges to work against. The wedges are successful about half the time, so, it is just as easy to proceed directly to step 2, drilling the chuck body.

Most arbors are either relatively soft, or case hardened, which leads to step 3, when the other two have failed. This entails sawing the arbor off close to the chuck body and drilling and boring the stub out on the lathe. Dismantling the chuck after chopping the arbor makes chucking easier. You can usually skin the stub out close enough to collapse the shell for removal.

[Circlip]

I know this is going to sound silly, but if you have dismantled the chuck again, you are so much closer to the bit you need to drill a hole in??

Regards Ian

[wierdscience]

Since you're ditching the abor anyway,weld a length of all thread rod to the end of the tang to use as a pull stud.Slip a piece of pipe over the arbor to bear up against the back of the chuck.Add a washer or two and a nut then tighten till it pops the arbor out.

If it refuses to pop loose put it in the oven at 225*and let the heat do the work.