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dp
03-04-2009, 12:23 AM
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
03-04-2009, 01:13 AM
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
03-04-2009, 01:15 AM
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
03-04-2009, 01:24 AM
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
03-04-2009, 04:34 AM
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
03-04-2009, 04:38 AM
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
03-04-2009, 04:45 AM
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
03-04-2009, 08:12 AM
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
03-04-2009, 08:26 AM
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
03-04-2009, 08:35 AM
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.

Bruce Griffing
03-04-2009, 08:42 AM
I did essentially the same thing as Weird suggests, except I cut off the back of the tang end of the arbor and threaded it rather than welding to it. This also worked. Using threads to pull it out results in a rather unexciting click when it gives - but it does work.

RancherBill
03-04-2009, 10:48 AM
That's what i thought, too, but it's not drilled through.

If you have the arbor out of the quill then you're almost there.

Tightly grasp the end of the arbor tang with Vise Grips and hang the arbor in a partially closed vise. Hit the chuck with a punch to drive it off. This is a four hands job, so if you are doing it yourself have lots of padding where the chuck should land and in spots where it shouldn't land. :) :) :)

JCHannum
03-04-2009, 11:03 AM
I wouldn't advise beating on the body of the chuck, it gets pretty thin outside of the area around the arbor and is easily damaged.

dp
03-04-2009, 12:59 PM
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.

I have a slide hammer and thought about this - and then I thought, what if it doesn't work :)

The arbor is pretty banged up but still serviceable so I don't want yet to destroy the thing until it's the last option.

dp
03-04-2009, 01:05 PM
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 ?

I think I'll drill it if I get it apart so I can use a drift punch next time. I'd like to save it, The scrolls and jaws are in excellent shape. No slop when holding the jaws face to face. I expected to see some wear or taper given the knocking it's gotten on the outside but the internals look good.

JCHannum
03-04-2009, 02:21 PM
There is enough of a void between the chuck body and the JT to permit drilling and tapping the chuck body with the arbor in place. You might need a plug or bottoming tap to complete the threading, but there is plenty of space to permit drilling.

Stepside
03-04-2009, 09:21 PM
Dennis
I have several sets of wedges. If I have the right size you are most welcome to borrow them.
Pete

RancherBill
03-05-2009, 12:59 AM
Dennis
I have several sets of wedges. If I have the right size you are most welcome to borrow them.
Pete

Would you post some dimensions?

It would be a mighty handy thing to have. It would be a perfect project for the Grandkids.

Thanks

dp
03-05-2009, 01:25 AM
Dennis
I have several sets of wedges. If I have the right size you are most welcome to borrow them.
Pete
Thanks, Pete - Jay saw your post and stopped in his tracks before mailing his wedges which is good. I can drop by and bring the chuck with and we and take turns whacking it to see if it will separate. After that dirty deed is done it would be my pleasure to take you to lunch. Bet we could talk Mr. Brock into joining us.

Stepside
03-06-2009, 10:42 AM
Dennis

I sent a PM with phone number. Also JB knows how to find me.

Pete

clint
03-06-2009, 11:48 AM
I oredered a set of wedges, however I could not wait until they came to do a small job, so I drilled through the center as mentioned in previous post, on my chuck it was very easy, I forget what drill size I used, however I have a big punch that I used to knock it out, I prefer this method now over the wedges. I just wrap a shop rag around the arbor, or you can put a box under/beside it to keep it from going airborne. I also done the drilling etc in the lathe, chuck te chuck up in a 3 jaw, drill in tailstock mounted chuck, took about 20 minutes including finding a drill I thought was the best size, finding the drill took longer than anything of course. I would not waste money on wedges again, especially if it's just a single order item..not a bad thing to have around if you were to add them to an existing order, this is all of course my humble opinion

JCHannum
03-06-2009, 12:59 PM
Drilling and either threading or simply using a drift to remove the arbor probably has the highest success rate. Using wedges works, probably, less than half the time provided there is an ample shoulder on the arbor for them to work against.

I dismantle and clean up or overhaul the Super Chucks frequently, and use the wedges fairly regularly. If it is for only a one time or very occasional use, save your money. There are four different sets of wedges that do not fit everything and don't always work on those they do. You have a one in four chance of having the right wedges and a 50% chance of them working.

If you do use the wedges, put them in place and use a heavy vise or press to put pressure on them. Beating on them with a hammer is not effective. They will spread with use, but can be squeezed back together.

Mark Hockett
03-06-2009, 03:00 PM
I dismantle and clean up or overhaul the Super Chucks frequently, and use the wedges fairly regularly. If it is for only a one time or very occasional use, save your money. There are four different sets of wedges that do not fit everything and don't always work on those they do. You have a one in four chance of having the right wedges and a 50% chance of them working.

Jim,
Do you have a good source for Jacobs chuck replacement parts? My industrial supplier wants more for a rebuild kit than the cost of a new chuck for at Enco. They tell me the jaws are no longer available individually. I have about 10 super chucks and I would like to replace the jaws on a few.

JCHannum
03-06-2009, 03:15 PM
Unfortunately, I have no source for replacement parts other than those supplied by Jacobs, which are too expensive in my opinion. They are not an economical alternate when good chucks sell on eBay for less than their cost.

The kits for the older series are available. They consist of the jaws and split nut assembly. Balls are available separately. McMaster Carr lists 2815A35, the jaw & nut for an 18N for $78.92. The kit for the new series is $226.09 which is ridiculous.

I attend quite a few industrial auctions, and occasionally run across repair kits at a reasonable price.

dp
03-14-2009, 09:11 PM
I stumbled onto a suggestion to another person on how to remove arbors without wedges. I drilled a hole across the diameter, put a short piece of 1/4" steel rod in it, and whacked it with a pickle fork. The arbor popped right out on the second whack.

I expected to find a rusted mess in the JT3 socket but there was nothing but bright steel. So I've managed to resurrect this old Jacobs chuck for no cost!

Thanks to all who offered to provide tools and suggestions.

http://thevirtualbarandgrill.com/machinery/2mtjt3arbor.jpg