Stuck lathe chuck...help!!!

[Typecaster]

I couldn't pass up a South Bend 9-in. lathe last year (the ways still show all frosting) even though I already had a Logan. Other than tarnish, the only problem with the SB is a stuck 4-jaw chuck. I've been squirting it with magic penetrating oil for 6 months to no avail.

I don't want to cut it off because it's the same thread as the little Logan...so I could use it on either one.

I think it could just be over-torqued, or a little rust at the spindle shoulder. Either way, I think it's so tight that the penetrating oil can't get past the shoulder.

I don't want to screw up the back gear. If I hit the boss of the chuck with the torch, would that expand it a bit...without ruining the spindle?

Any suggestions?

Richard

[lathesmith]

Type, Take a piece of hex stock--say, 1" or bigger x 3" or so long-- and mill 4 flats on the sides, maybe halfway up the length. Chuck this as tight as you can in the 4-jaw, get you a 1/2" or bigger impact wrench, and use the impact wrench on the hex stock with a socket. I guarantee you WILL break it loose this way, IF you have a big enough impact wrench. It shouldn't damage a thing, either.
Good luck,
lathesmith

[Morgan Astorbilt]

For this purpose, you can hold large enough hex stock in a 4-jaw just the way it is. The jaws will hold two adjoining flats on each side with two opposing flats free.
Morgan

[mike in co]

home made impact...

take a piece of solid bar..any shape 1 1/2 " or bigger,about 2-3 feet long, chuck it on the face of the chuck, between a couple of jaws.( 90 degrees from the centerline)
with it sticking out give it a solid whack with a bmfh........thats a single impact...if more needed do so. dont do a ton of pounding in anyone position....dont want to beat the bearing races.


mike in co

[gzig5]

You didn't say what kind of penetrating oil you are using. Beg, borrow, or steal some Kroil. Can be hard to find local, but lots of places online carry it. Let it soak for a couple days and then try and take the chuck off. If it doesn't come, you need heat. You just need to get the area around the threads hot, not red hot but hot. Heat ALWAYS works.

If the chuck has a seperate backplate, I would recommend removing the chuck and put a couple bolts in the holes in the plate to use for leverage with a large pipe. This way, you won't spring or damage the jaws. One SHARP blow with a 3-5lb hammer and it should let go. Worse case if for some reason it won't let go, you can always turn the backplate off of the spindle.

[wonderwolf]

+1 Kroil...I love the stuff on guns as well :Fire:

[10-x]

+2 for Kroil...remember if you use heat get a Temp Stick to make sure you do not overheat the bearing(never over 250 F):-D

[Cactus Farmer]

+3 for Kroil. It really is magic! They claim it will find a .000001 crack and I believe it.

[Antietamgw]

Another thumb up for Kroil! I got mine online in a gallon jug, directly from Kano. I consider it cheap if you get the liquid.

http://kanolabs.com/

It's about twice the price now that I paid and is well worth it! I needed to pull a barrel from a Ballard that had seen better days. Didn't want any marring on barrel and sure didn't want to tweak the receiver. Gave her a shot of Kroil everytime I thought about it for a couple days. Made a close bushing for the barrel vise, set it up after blocking the inside of the receiver, brass shims for protection and all the other little tricks I knew. Said an extra little prayer and thumped the end of my 3' action wrench handle. It broke free so easily that the handle came around and whacked me on the shin. The Kroil had soaked to the roots of the threads over the entire length. Great bore cleaner though I heard it wasn't a very good preservative. I use it on everything from guns to farm equipment. MUCH better than PB Blaster, Liquid Wrench, etc.

[HeavyMetal]

What I have done to remove tight chucks on my Southbend.

Make suire it's unplugged, put any stock you want in the chuck and tighten it. engage the back gear but don't unplug the head, now put a 15 inch Cresent wrench on one of the jaws and unscrew it.

Lefty loosy righty tighty.

[trevj]

Absolute worst case scenario, disassemble the spindle and slide the spindle and chuck out, and do your work on the bench.
Parts diagrams and other such info are out there on the web, so do the research first, and it's really no big deal to get it apart and back together again. If you have to.

Since you already have a lathe, you could turn up a sleeve of hex stock, and key it to the spindle, to allow the chuck to be held in the bench vise while you gently but firmly apply the pressure to the spindle with an appropriate wrench.

Most of the time, someone allowed the chuck to tighten by starting the lathe after the chuck had been started, allowing it to snap tight. Not so good. Other times, it's just old oil turned to varnish, in which case, heat and thin oil or solvent, are the thing.

I'd try applications of heat (paint stripper gun) to somewhere just a little less than to have a wet rag sizzle when touched to the chuck, in combination with the penetrating oil. A couple cycles of heat and cool will often do wonders to get things to flow into the tight spaces.

I'm kind of surprised that the SB's don't have provisions to lock the spindle other than using the back gears. Would make life a little easier for situations like this.

Best of luck.

Cheers
Trev

[arclight]

Funny thing, same thing happened with a South Bend I found on Craig's List. What worked for me:

1. Penetrating oil on the spindle
2. Remove top cover. Cut out a wedge from soft wood and use this to jam up the bull gear from turning.
3. Get a strap wrench from the hardware store. This is what really did it for me. Clean the chuck with solvent so that it doesn't slip, and then wrench on it. Should make a loud "pop" and start unscrewing.

Good luck!

Arclight

[PatMarlin]

Well did ya get the beast loose?

[Typecaster]

Woo-hoo! It's off!

I've been going real slow on the little lathe…at least until I finish the 11-in. Logan rebuild. I didn't want to take any chances with the backgears and a BFH, and I didn't use heat. I did give it a squirt of Kroil every time I was in that part of the shop, and maybe a tap on the hub, and once in a while I tried using a strap wrench on the cone pulley. No luck. I was seriously thinking of turning it off, but noticed that it's a Logan chuck, and I don't have a 4-jaw to fit my 10-in. Logan.

This morning I put a spacer between a couple of chunks of aluminum bar stock, mounted the assembly on the faceplate of the little Logan, and bored it out to fit the end of the South Bend spindle. Just like bushings for a barrel vise. Added a little rosin and cinched it down to a couple feet of heavywall square tubing for a handle, and rested the handle on a block of 4x8. Put a chunk of bar stock in the 4-jaw chuck and gave a mighty bounce on a BF Crescent wrench. Butt-ugly, but it worked!

Next question—just give it a solvent scrub and re-oil, or a complete teardown? The old guy I bought it from hadn't used it since 1960 when he had to move into an apartment, and it just sat in a storeroom under plastic. He only played with it a little after he bought it, so there's absolutely no wear, just oil on the paint that's turned to varnish…everything spins freely.

Thanks for all the suggestions, gang!

Richard

[badgeredd]

It would probably be wise to change any oil in it. At shops I've worked at that was SOP because one never knows how contaminated the oil is or how old it is.

Edd

[Buckshot]

.............I believe Logan branded chucks were made by Buck.

.............Buckshot

[Cactus Farmer]

Congrats on your success at removing the chuck. You have a nice tool and it's condition sound like my inherated SB 7" shaper. It is all but new<should say was>.
I have a 7"logan floor mount also that has the variable speed handle in the front of the pedastal. It came from a ranch down by Rock springs and had 5# of mud dauber nests in the tower.Sounded like a thrashing machine.I bought it for scrap price because of the noise.
The South Bend is a bench mount and both are so nice....why do I need two of the same size? They each do things that their shop mate doesn't do as well. Plus I keep one vise at 0 degrees and the other at 90. Dialing in a vise is a PITA. The South Bend is my "go to" screw slotter. No screw slot width escapes me! I know shapers are old technolgy but they are the bees knees for one-off parts and fixing SNAFUed and odd dovetails. Old buggered up screws are UGLY and it isn't that hard to make new unchewed-up ones. My customers sure like the service and it makes an old friend look like someone cares about it.
Take care of these old machines,they sure don't make 'em like that anymore!
I just wish some of mine could talk,....old guns too!

[scrapcan]

From the pictures the old girl looks to be in good shape. I would pull it down and do a good cleanup and then lube it up. You should llok at becoming a member of one or several of the southbend groups on yahoo. All the info you need is there. or look up steve wells + south bend. he has a good set of pages also.

[PatMarlin]

.............I believe Logan branded chucks were made by Buck.

.............Buckshot

Can runout be adjusted on 3 jaw chucks?

[Typecaster]

Pat, I don't think so. Seems to me that there's a scroll gear that moves the jaws, and I don't think there's any adjustment. But, then again, I haven't taken one apart for a metal lathe.

My dad (98+) said he put a dab of different colored nail polish on each jaw to tell which was which and could add shims to minimize runout, but he preferred to use a collet or fuss with getting a 4-jaw dead nuts on. I guess you could do one test and keep the notes, then work of any other size would get the same shims? I guess it's a little easier than using a 4-jaw, anyway. I wonder how repeatable it would be when you remove/replace the chuck.

OTOH, when I was doing technical glassblowing (laser tube parts, etc.), we just would heat the tube near the headstock, gently support the tube over the bed on a "fingertip steady rest," and when the tube softened it would bend to be concentric. You develop a feel for when it's straight, and the reflections of the lights in the shop were a pretty good indicator…if the reflections were steady, the work was straight. We'd almost always toss the stub that was in the chuck, so straightening the work was the easy answer.

[bohica2xo]

This thread made me smile when I looked at the L00 spindle in my Heavy 10 this morning.

I don't know what that option cost new, but the guy that sold me the machine thought he had to give me a deal to take the "oddball spindle" (snicker).

I wish the Tarnow had an "L", but the D1-8 is still better than threads.

B.

[gzig5]

Unless there are chips and junk in the backside of the apron or in the gears, I'd leave it be. Life's to short to pretty up working machines just for the sake of looks, I think. These machines are total loss lubrication, so any oil that goes in will eventually end up on the floor and will flush out any old varnished oil. Just make sure that all the oiling points are not plugged and allow the oil to get where it needs to go.

[Buckshot]

Can runout be adjusted on 3 jaw chucks?

............There are adjustable 3 jaw chucks just like 6 jaw and 2 jaw adjustable chucks. Without going into a lot of explaination it basically takes a special backplate that the chuck body can be moved around on, then locked in place. Adjust -Tru (or whatever each manufacturer calls theirs) chucks do have a slightly different body to work with the special backplate.

By altering a standard backplate for a 3 jaw chuck you can fab up your own sdjustable chuck. I know one of the HSM magazines or project books had a "How to do" article about creating one. Of course they're only going to be truly adjusted 'in' for that particular size of stock, or item you're wanting to machine, and usually to about .0005".

I have 2 adjustable Buck chucks. A 6 jaw and a 2 jaw (haven't even used the 2 jaw in 5 years) but the thing for me is, if it'll fit into a 5C, I use the 5C. In fact I have a 5" 3 jaw and a 4" 4 jaw on 5C backs simply because I'm so lazy, and 90% of my chuck work fits them it saves me from breaking down the 5C closer to put on a bigger chuck. [smilie=w:

...............Buckshot

[PatMarlin]

Yaw cuz...

Everthing I do is primarily based on 5C. I love the 5C backed 3" chuck (chinese) I have but I crashed into the darn thing about 3 times with this CNC until I got a handle on it, and now it's bout' .004 out.

I noticed Bison had a 3 jaw adjustalbe, 5C backing plate model all within a TIR of .0005. That may be my next purchase, as that chuck is so handy, and I can swap it in between my 3 lathes.

I haven't got the Vari-grip collet closer to work on my Hardinge CNC as yet, so I've been using the 5C chuck.

[trevj]

Can runout be adjusted on 3 jaw chucks?

If you have one using a backplate mount, rather than an integral mount on the back of the chuck body, then, sometimes.

The Buck Adjust-True and Burnerd Grip-Tru chucks use a loose fitting register and some adjustable screws to allow centering up at least one particular size of stock at a time, by loosening the mounting bolts, adjusting the runout using the screws, then re-tightening the bolts.

You can sometimes take a shave off the OD of the register between the backplate and the chuck and adjust by tapping the chuck to center it up. Again, only really good for one size of stock at a time, the one that the chuck had in it when you adjusted it.

Better'n nothing!

Cheers
Trev

[PatMarlin]

I'll have to fidle with it today maybe.

It would be nice to have the air powered Vari-grip Hardinge CNC collet closer on my lathe working, BUT it may eat me out of house and home if it did. They are made to leak air. The whole lathe is made to operate with 20 psi minimum as it operates the lube system, and keeps the turret locked in place, and that leaks out in various places. It's spossed to.

If I was to use the collet closer, it may require upwards of 80 psi, and I can't afford to run (cycle) my compressor any more than it is. It took a mountain of effort (yes MR. Obama it was hard- oh my!), to modify the 3 phase machine to run on single phase 120v, but I wasn't counting on the Hardinge air leakage factor. I can live with loosing 20 psi.

So what I do now is program a stop at the end of a part program, or sequence. Open the chuck, and pull the stock out to the stop. Hit start and walk away. Then repeat. Beats the pants off of standing there running the part on a manual machine still, and allows me to work on other machines.

Kinda wish the machine had the same lever collet closer as on my manual Hardinge. That closer is sweet- very easy to use and smooth.

I went and purchased a Dunham bar puller before I realized the collet closer had some issues and about the air leakage. Very cool tool, that was bout' $250 for 3 sizes fo stock. Now I may never use it.

[JIMinPHX]

It took a mountain of effort (yes MR. Obama it was hard- oh my!), to modify the 3 phase machine to run on single phase 120v,

You can get an M/G set or use a VFD to produce 3 phase out of standard 120. Let me know if you need more info on that.

[JIMinPHX]

This is how I usually handle a stuck chuck

[PatMarlin]

You can get an M/G set or use a VFD to produce 3 phase out of standard 120. Let me know if you need more info on that.

For a 3.2 kw DC motor cnc control?

All I had to do once I finally comfirmed my suspisions with a good electronic tech was swap out one transformer ($700) and jump some contacts.

The machine had a 3 phase input, but then split off into single phase 220v, then all the servo amps and spindle motor- everything was single phase 110-20v at the end accept for the stupid coolant pump.

It just took weeks of having various folks say I couldn't mod the machine like that, when I had enough basic knowledge to know it could be done. Finally I found a guy that builds custom amplifiers- we sat down and went over the schematics, and wala- figured it out.

[JIMinPHX]

Sounds like you have it under control.