View Full Version : yet another "removing stuck chuck" question

J Tiers
06-19-2004, 07:58 PM
Got a "nice" LW dividing head today.

Cleaning it up, I found that it does have the inevitable one serious problem.

The chuck (1 1/2-8, apparently) is stuck, and isn't wanting to come off. Looks like it might have some rust in that area, although the rest of the "rust" was really just discolored and solidified grease or oil.

I have various concoctions for loosening rust, P'blaster, etc.

The question is how to apply force without risking damage to the worm setup. I don't think I want to pull the spindle if I don't have to, as it's not loose, seems OK. I'd have to take off the gear, and the rear nut, etc, which seems excessive....

I can set up on the spindle lock, but that doesn't seem to make it particularly any safer to reef on or "tunk" on the chuck (or on a piece of hex clamped in it, actually). I kinda need to get the chuck off for cleaning and/or disposal, I think its junk.

Not much spindle sticking out....


Paul Alciatore
06-19-2004, 08:24 PM
I think you are right in not wanting to risk damaging the worm. If there is enough spindle available behind the chuck (1/4" or so) I would try to fabricate a strap wrench with steel strap and a piece of stock of the same width.

Of course, you should soak it in your favorite penetrating oil for a while first.

Paul A.

Bruce Griffing
06-19-2004, 08:35 PM
Can you disassemble the chuck in place? If you can remove the gear sleve, thread and jaws, you will have easier access to the back of the chuck. It may be open the the threads or you may have to drill into it. Access to the other end of the thread will allow you to try lubrication first. Failing that, I would try cut the chuck body in half without going down to the threads.

06-19-2004, 09:18 PM
If your L&W dividing head is like mine,then the worm is on an eccentric which which can be rotated out of mesh with the worm gear and consequently pulled out of the housing.

It's pretty straight forward except for two set screws in the top of the housing that are perpendicular to the worm shaft. Their function is to keep the worm shaft bearing,which contains the eccentric,where you set it.

There is no roller bearing on the spindle,just bare metal to metal.The back bearing is just a straight bore while the front big bearing is tapered.The lock is just a screw pushing against a brass plug that pushes against the tapered bearing.I don't remember whether the thrust bearing is a brass washer or what.

If it were me I think I would pull the worm out and run one jaw about flush with the OD and flail the hell out of it,in a counter clockwise direction of course and after it was saturated with P oil. http://bbs.homeshopmachinist.net//confused.gif

Jim W.

06-19-2004, 09:31 PM
JT: Does the worm have a little bit of backlash to work with ... if so how about if you tighten the lock with the backlash NOT taken up (in the unscrew direction). Then, apply gentle "impact wrench" style taps somewhere on the circumference with a brass or aluminum bar.

After a few test "taps" loosen the lock and see if the backlash is still there. If so, the lock protected the worm against the taps ... tap on, continuing to check periodically for the sake of the worm.


J Tiers
06-19-2004, 10:19 PM
drof: I don't think it is like yours. There is just one (double stacked) setscrew in the top, and the other pic shows the plate side has a bolt-on piece.. no sign of an eccentric that I can see.

As you can see. not much to grab anywhere. Might have to figure out how to get it out so I can hold the spindle.

In the first pic, the object along the bottom is a 6" rule that didn't get quite in the pic.



Also, looking at the first pic, there is a hole at the bottom. The bracket (one side, not double) has got a hole corresponding. Do you suppose it would have had a detent? Neither hole goes through.


G.A. Ewen
06-20-2004, 12:06 AM
If you are ABSOLUTLY SURE that it is threaded on you can try this. It has worked for me every time.


Mike Burdick
06-20-2004, 12:12 AM

Now that's clever! When one sees a good idea no words needed.

(should put that in the tips book)


J Tiers
06-20-2004, 12:19 AM
And I would if it were a lathe. But that worm and gear has me worrited. I don't want to strip teeth.

It is kinda like using back-gear for a lock, which wouldn't be too cool with impacts. Only I can't disengage the gears and use the rotating pulley mass as a counterpoise, as I might with the lathe. There isn't any mass to speak of, aside from the chuck.

I am not even too sure how to disassemble the thing further, even though it is pretty simple appearing.

And, of course, I have something for it to do, scheduled for the day before yesterday....so a chance of damage isn't really wanted. This stuck chuck was a surprise I didn't need.

I figured I could get it off and put a good chuck on it, grease and oil it, and get going. A full clean and so forth could wait until I had cut the one gear I need to cut....

G.A. Ewen
06-20-2004, 12:27 AM
One pull of the trigger is all it takes (about 30 seconds) The last time that I had to remove a stuck chuck was for a friend. He had got a bit hyper before calling me and had broken 4 teeth off on his back gear. He almost cried when he saw how easily it came off with the air chisel.

Neil can use it in the tricks book if he likes.

Mike Burdick
06-20-2004, 12:47 AM

Would you be willing to put some heat to it?
If I understand correctly, you don't care about the chuck.

J Tiers
06-20-2004, 01:04 AM
<font face="Verdana, Arial" size="2">Originally posted by Mike Burdick:

Would you be willing to put some heat to it?
If I understand correctly, you don't care about the chuck.

That is a possibility. I THINK the chuck is bad, but won't be certain until its off and I can disassemble it sometime. Won't come apart now, can't get to the screws with enough torque as is.

My experience with heat removing things has not been good. Basically it has not worked well in this sort of situation for me, at least not as far as differential expansion etc. Everything heats together.

Maybe heat will just loosen the "crud bond". That does sometimes work, depending.

So long as it isn't galled on it may be fine after soaking longer, too.

But I can't see how to get a good torque on it.

The ID is a taper, probably B&S, which I have no taper tooling for. I suppose I could make an expanding arbor, or draw-in piece, with a hex or hole thru etc.

But I would be a bit afraid of expanding the spindle though. The piece might take quite a bit of drawing-in to withstand the larger lever arm of the OD thread, and it will have to come out again someday!

Hmmm, its coming off, I just dunno yet how. Hopefully I won't have to turn the whole dang thing off the spindle. Its about a 5" chuck.

G.A. Ewen
06-20-2004, 09:39 AM
J Tiers,
If you tighten the lock on your dividing head you won't hurt the worm gear with the air chisel. It is the high speed rapping that does the job not brute force. The fellow that I mentioned earlier had put a 2x4 in his chuck and hit it with a 3 lbs hammer. (no wonder he broke the back gears) A strap wrench around the spindle pully is all that it takes to hold it for the air chisel.

06-20-2004, 01:22 PM
Brilliant idea.
The picture if the air chisel makes me flinch because there's no board on the ways. Of course it's just a photo to show the idea, you probably weren't actually using it then?

06-20-2004, 01:48 PM
That is excellent George. I will keep that in mind.


I don't think you need to worry about the worm. Each hit of the hammer is no more than a light tap. Think about it, the mass of the piston in the air hammer is only a few ounces. I bet it works just fine. Jam the worm with a hardwood wedge.

06-20-2004, 08:35 PM
Evan: Don't forget that the same little hammer cuts mufflers and pipes off exhaust systems with no sweat.

I'd suggest leaving a little backlash, locking the spindle, tapping a little and checking to see if the lock held by seeing if the backlash is still there, "ahead" of worm contact. Gee, that's as clear as mud isn't it http://bbs.homeshopmachinist.net//smile.gif

06-20-2004, 09:15 PM
Basically, your dividing head is like mine with a few differences.First yours is a lot smaller than mine. There is an 8" chuck on mine and the threads are 2/something x 10TPI. It appears on the indexing plate side of yours that there is a keeper plate with a nut holding the indexing plate flange on. If you take that nut off and make sure the plate under it is loose and take the two stacked vertical set screws out,you may be able to rotate the indexing plate flange. It appears that this flange and its body is also the bearing for the worm shaft and the OD of this flange body on the back side where it goes into the main housing is probably eccentric to the worm shaft bearing. Turn the flange almost 180* while trying to turn the worm shaft and see if it comes out of mesh with the worm gear.It may only turn one way depending on which way it was rotated into mesh. If this works then this means the worm is in a cantilevered configuration with no radial support on the opposite end. It does however have a thrust bearing for axial support which you should be able to see at least the adjustment for it at the stage of disassembly you are at now.
It's past time for me to hush.

Jim W.

J Tiers
06-20-2004, 11:03 PM
Thanks for all the advice.

Got it off, had to disassemble the unit to the last screw and nut. But that's OK because I need to replace at least one thrust bearing. And now the 40 years of crud has been cleaned out.

Once spindle was out, I remembered I had a couple things that look like pillow blocks, but are not. They resemble wrenches used in gun work to hold barrels, two heavy bars with a hole thru the split and big studs to hold them together. About 1 1/2" bar steel.

I clamped the parallel portion of the spindle in one of those, with the key held in the gap between upper and lower piece, and clamped that all to the bench with the chuck just supported. A piece of 1" hex in the jaws, and a foot-long 1" box wrench whacked with a lead hammer did the job with no damage to anything.

Incidentally, if you ever have to take one of these apart, the woodruff key for the worm wheel has a slot cut in the front bearing for it to pass thru. It works substantially better if you aline the key and the slot when you pull the spindle, as there is no other way to get it apart! I figured it out before damage was done, it was covered by crud and invisible.

That piece that holds the worm shaft is one piece, not two. There isn't much room to move, but I assume I have to move it around for best fit. A setscrew in the case holds it down, and may allow a finer setting, I need to check that when I re-assemble. I should take a pic and post it in this message so you can see what I mean.


On the near portion of the bracket nose you can see a depression. The setscrew on top of the case fits into that, alining the worm, and maybe pressing it into full engagement.

What is the guessing for lubing this divider head, oil or grease?

Worm shaft has two ball thrust bearings, plus two oilites in that bearing housing. Main spindle has one at the back. Front is a taper bearing, very shallow, it can lock up (self-locking taper!).

The case had two beat-up "ball oilers", but they could have been intended for grease. I am not sure what I cleaned off of it, could have been either grease or solidified oil.

BTW, the chuck turned out to be pretty good, so I cleaned it up. For what I paid, the chuck is free.

Thanks again

[This message has been edited by J Tiers (edited 06-21-2004).]

05-24-2012, 04:56 PM
I have to bring this thread up from the dead, to thank G.A. Ewen for his most excellent application of the air hammer. I'm in the process of disassembling an old Cincinnati dividing head which suffered from the usual stuck threaded chuck adapter.

Initially, I thought I could remove the spindle and deal with it on the bench, until I discovered too late that the spindle comes out the rear! I considered building a strap wrench to grip the indexing collar but I noted that the indexing collar is held to the spindle by only four #10 screws.

So, I did a google search and came across Mr. Ewen's method. It took about 5 seconds, max. Literally Burp! Burp! and it's loose. Beautiful!

Mr. Ewen, you saved me at least a day of labor with that little post. Thanks!

Photographic proof:




05-24-2012, 05:42 PM
What I would try:

If the worm can be rotated out of the gear do so, place a piece of hex stock in the chuck (3 jaw assumed) and use an impact wrench with socket on the hex stock to loosen the chuck. Even with the spindle free to turn (worm disengaged) there should be enough friction with the rapid impacts of an impact wrench to loosen the chuck. No damage to the gear or worm should occur because they are not engaged during the process.

My theory on this is confirmed by the method used to remove a bolt from a crankshaft damper on an engine. Even if the engine isn't locked in place and can turn freely the impact wrench will still break the bolt loose.

Oops, too late! Glad you got it off anyway.