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View Full Version : 4-jaw removal cornfusalment



tony ennis
11-08-2007, 08:46 PM
Ok, this 4-jaw hasn't been off the lathe in 2 years at least - that's when the previous owner passed. And there were no additional chucks or faceplates. I can only conclude that this 4-jaw may have been on the lathe for a very long time.

How do I get it off? I've thought about it so much I'm completely confused. It's a Craftsman 12".

The chuck needs to be spun clockwise to be removed, yes?

Fasttrack
11-08-2007, 09:12 PM
Not sure but the cincinatti at school has a taper-key spindle and the chuck un-threads counter clockwise. Also i think the southbends with threaded spindle noses were right hand thread so you spin the chuck counter clockwise to get it off but i've never worked with one...

BadDog
11-08-2007, 09:16 PM
I don't know the Craftsman 12", but I'm pretty sure they were all threaded spindles. So, there should be some means to lock the spindle against rotation. Then chuck should have some feature for attaching a spanner or some sort of bar to turn it counter-clockwise (standard right hand thread) and unscrew the chuck. Don't drop it on the ways!

If it's been on there a long time, it may be necessary to get more "serious" with it. I've head of folks putting a board under the chuck to protect the ways when/if it drops, then clamping a board in the chuck jaws, extending from one side over the ways. They then run it backward in back gear to break them loose.

matador
11-08-2007, 09:17 PM
Errr,no.the chuck needs to be turned anti-clockwise for removal.If it was the other way,your chuck would spin of at the first sign of a load on it.
That is to say,if your standing in front of the lathe,with the headstock on your left,spin the chuck towards you.If possible,lock the geartrain,or at least in the lowest gear possible.Chuck a piece of scrap steel in the jaws,so it sticks out beyond the chuck.Hit this bit with a good size hammer,and it should free up.
If it doesn't come off,spray wd-40 or similar on spindle thread,and leave overnight.Should come off nicely in the morning.
If it doesn't,I'm out of ideas:).

matador
11-08-2007, 09:19 PM
btw.Baddog's point about a board on the ways is a very good one.I use a cheap polypropylene cutting board for this very purpose.

Herm Williams
11-08-2007, 09:40 PM
If you put it in back gear and put too much pressure on the gears you may break a tooth on the backgear. If I was removing a stuck 4 jaw chuck I would put an inch bar in the chuck and use an eight point socket with an air wrench after soaking it for a week or so with liquid wrench or a similar penetrating oil. I would use a strap wrench on the drive pully instead of back gear. If all else fails you may have to remove the chuck from the backplate and turn it off.
my two cents worth, I would interested to know how you finally get the chuck off.

Carld
11-08-2007, 09:40 PM
The chuck is threaded on with a right hand thread and is removed by turning counterclock wise as matador said.

Put it in back gear and run one of the jaws out to the OD of the chuck. Take an 8" +/- long piece of 3/4" key stock or something similar and lay one end of it flat on the face of the chuck perpendicular to the jaw at the outer edge of the face. Hit it smartly with 1 or 2 pound hammer. A few hits should do it. Be sure the end of the bar on the jaw is square and flat on the jaw. It is important to hit the jaw at the face of the chuck, not away from the face.

This is the way it is done in almost all machine shops. But if you are a purist and fanatic then there are ways to spend hours and/or days to remove it.

EDIT: You can use the lowest gear without the back gears and sometimes it will break loose. As mentioned in following posts, the back gears are sometimes easy to break.

jacampb2
11-08-2007, 09:44 PM
When I removed my 3 jaw from my L1 nose, presumably for the first time in a zillion years, I had a lot of trouble. I put 2x6s over the bed, put a big high quality prybar between the chuck jaws and bound agains the 2x6s. Put my spanner wrench on the chuck lock collar and couldn't buge it. I ended up with a 8' extension on my spanner and actually rocking the 15x48 lathe onto its feet before the collar finally broke free. The manual said specifically not to put a extension on the spanner, but I didn't have any other choice. I had soaked it in penetrating lube for days. It was to close to seals and the Gamit bearings to risk heat, so it had to be leverage. I nearly had to change my shorts when the collar let loose, it made a huge bang! All is well now though, and the threads are antiseezed...

Later,
Jason

SGW
11-08-2007, 09:48 PM
Be careful on your bashing, that you don't break the back gears or the locking pin.

First thing I'd try is putting it in backgear and don't pull the locking pin; this ought to lock the spindle against rotation. Arrange to have one of the chuck's key holes on top of the chuck. Insert chuck key, and give it a vigorous yank towards you. If you're lucky, that will be sufficient to start the chuck unscrewing.

If you're not lucky, more persuasive measures will be needed, and at this point my initial cautionary sentence about being careful not to break something kicks in. I would be careful of doing anything much more forceful and relying on the back gears to lock the spindle. I don't think Atlas gears are known for their strength. Figure out some other way to keep the spindle from turning. One thing you could do, though it would take a bit of preparation, is clamp a couple of pieces of wood together with two bolts, then bore a hole between them on the dividing line just big enough to go around the spindle. Use the boards and bolts to clamp the spindle in place -- you might have to shave a little off the boards' mating surfaces to get clamping to happen. Then stick a bar between the chuck jaws and belt it with a hammer, as somebody else suggested.

CCWKen
11-08-2007, 10:16 PM
Don't use the indexer pin or you may break it or the pulley. I engage the back gear lever, stick the chuck key in one of the pinions and give a yank towards me. Don't put anything in the jaws and hammer. Use a piece of wood across two jaws and tap. Before I'd do that though, I'd use a rod in one of the pinions and hammer. Less chance of breaking out a jaw.

J Tiers
11-08-2007, 10:29 PM
I do exactly what CCWKen does.

I am in general AGAINST hammering on things in a gear train, unless the gear train is as stout as the ones in machines CarlD is used to.

That Atlas ain't a Springfield. You actually have a pretty decent chance of breaking something on the Atlas. Not so on a Springfield, or other big-A heavy machine (substitute favorite big-A machine names as needed).

IMPACT cracks Atlas gears (and ones in other lightweight machines). A steady pull, even with a lever does not have as good a chance of breakage, so that is what I'd try if a good pull with the key isn't good enough.

P-Blaster is good stuff for stuck things.

tony ennis
11-08-2007, 10:41 PM
I don't have the countershaft nor back gears on my lathe currently. I want the chuck off since it seems like a requisite for removing the spindle.

I tried putting some 3/4" oak in the jaws and striking it with a hammer.

I held the cone pulley with my hand and struck the oak with a 16 oz claw hammer. I did this repeatedly. I eventually broke the oak. The chuck didn't budge. I hosed it down with WD40 though I don't think it's going to do anything. Maybe it will find a way in, we'll see.

Stay Tuned.

J Tiers
11-08-2007, 10:47 PM
When using a hammer, hitting a lot with a light one is not equal to a couple of good "clugs" with a big one......

if the gears are not in, you can't break them, so go for it, just don't damage the bearings, or bend the spindle by getting vicious on it.

tony ennis
11-09-2007, 12:33 AM
I think I'll try a cheater bar and strap lock. I don't want to beat on it.

dicks42000
11-09-2007, 06:57 AM
The 2 lathes I have that use threaded spindle noses have both been subject to the "lock the spindle with the back gear" routine and the chucks come off fairly easily. It is the recommended method in the Atlas 6"/10" manual.

Yes, use a chuck board to protect your ways. 30 to 50 lb. chucks can hurt your fingers & bruise ways. Lathe beds don't heal well.

Never had a problem with the D1 spindle nose on the other lathe.

The SB wore it's 3 jaw for a number of years without removal; I just used a piece of 2 x 4 between 1 jaw & the bed and rotated the spindle by hand from the pulley. Banged a few times, but it came off. I can't recall if the back gears were in for torque multiplication or not though....

Rick

oil mac
11-09-2007, 12:56 PM
On occasions i have had the same problem, This worked for me, Make a block of wood, distance from below flat edge of chuck jaw down to bed, Something like a miners pit prop, Place under rear chuck jaw, Next engage back gear, And if one can, Grasp primary drive pulley belt from motor to countershaft (And with all electrics switched off__important!,) Grasp belt & rock chuck forward towards you, then a bump back, not too violent, after a few bumps, it should come off, if not a mild heat on the backplate boss behind chuck, using gas flame, to assist. Protect lathe from flame, you dont need a lot of heat, just warm to touch Using wood for a bump shock is more gentle on the gearing, bearings etc, than striking any chuck parts with metal.

With screw on chucks, one dreads a cutting getting between the faces of the backplate register, That can cause real problems, I once encountered an occasion with an old Harrison lathe, where it fought to the last section of the register leaving a badly torn surface on the face of the mandrel

Swarf&Sparks
11-09-2007, 02:16 PM
try locking the spindle from the back.
On small lathes, pushbike stem will do it, complete with handlebars.
If that doesn't quite fit your spindle bore, cobble up something that will fit.
You know the sorta thing? Drill through a piece of round bar, cross-cut at an angle and run a bolt through it. The shear action will lock tight inside the bore.

BadDog
11-09-2007, 02:56 PM
Man, you guys are making me SO glad I no longer have a threaded chuck! <grin>

Frank Ford
11-09-2007, 06:41 PM
I no longer have a lathe with a threaded spindle, but when I bought one (my first lathe) from a friend, he showed me how to remove the six inch chuck by sticking a strong hardwood piece between the jaws, and resting the end on the bed of the lathe. Then in lowest back gear, he'd "blip" the reverse motor switch, and the chuck would unscrew itself part way without dropping. He also protected the ways with a board to avoid banging into them, but neither he or I ever dropped the chuck off the end.

The chuck always went on with clean grease or oil, and I continued using that practice until I passed the lathe to a new owner. Never had a problem, but is that generally considered an uncceptable method for this size machine? Is it ultimately hard on the lathe or the chuck?

kendall
11-09-2007, 07:28 PM
The bicycle handlebar stem works well if the spindle through hole is the right size, gives a good solid grip and eliminates stress on other spindle/headstock parts. I've used the same on several lathes.

Ken.

tony ennis
11-11-2007, 12:04 PM
The continuing saga is that I have made no progress. The issue revolves around me being unable to hold the spindle. I don't want to jam anything into the bull gear. I wrapped an old leather belt around the bull gear, but it slipped then finally broke :-/ Well, the buckle tore off.

I did have a bit of a "duh-piphany" today. I am not trying to remove the chuck from the lathe. I am trying to remove from the lathe the faceplate to which the chuck is bolted. I removed the chuck and examined the faceplate - there are no set screws, etc. The end of the spindle is visible. This gives me another PB-Blaster target.

As an aside, if the bull gear or face plate was somehow irreplaceable, like it was a true antique, I have a hard-core solution: Dam off the top several teeth (the more the merrier), and pour lead over the them. One solid block that's flat on top! Once it solidified it would act as a "wrench" that I could strap down tight. Now all the force would be borne by many teeth, not one.

In my case, however, I'd sooner turn the face plate off :D

pntrbl
11-11-2007, 12:32 PM
If the backgears are still in it could you stick a penny between it and the bull to jam it? Hopefully it'll eat the penny before you break anything, but that sounds like one stuck backplate.

SP

tony ennis
11-11-2007, 12:36 PM
Mostly it is my inexperience, coupled with my inane lack of desire to risk a $20 part, and finally the lack of a back gear.

Now that you mention it, however - the back gears are ON the the lathe, but won't engage because the spindle's been fiddled with - the gears no longer line up and one of the back gear will strike the cone pulley. That's why I need to get the spindle off... I'll see if I can wedge something in there...

Paul Alciatore
11-11-2007, 02:15 PM
I've seen this come up several times before. Yes, threaded chucks use a standard right hand thread so CCW to remove.

A word of caution. I have seen many lathes advertised on E-Bay with broken back gears. I strongly suspect that most of them got broken during chuck removal. This could be an expensive repair.

The first thing I would do would be to soak it in some penetrating oil like Liquid Wrench for as long as you can stand. A week would be good. Drip some on every hour or so or make a dam and fill it for constant soaking. If you can remove the chuck from the back plate you can add the oil from both directions.

I like the bicycle handle bars idea. It is probably the best way of holding the spindle without endangering your gears. A piece of hardwood in the jaws is also good. Or a really big strap wrench around the OD of the chuck. I would try repeated blows of a moderate force before giving it all you got as heavy blows are more likely to damage things. The repeated vibration of many lighter blows can help the penetrating oil to find it's way into the threads. You could do this once or several times a day while soaking it. Then, if all else fails, give it a FEW good ones.

Worst case, you can remove the chuck from the back plate and turn the back plate off. You should be able to miss or just kiss the tops of the spindle threads. If it comes to this, you will probably find rust in there. Some clean up work on the spindle may be needed. Of course, you will need to make a new back plate.

I don't understand why the lathe manufacturers do not make a simple but safe spindle lock for this. All it would take is a hole in the appropriate location.

Daminer
11-11-2007, 02:15 PM
I've had Atlas craftsman lathes for 30+ years now, and the threaded spindles are definitely one of the more undesirable features.....

You say you're down to just the faceplate on the spindle?....If so, get a heat gun (hot air) when the ambient temp. is low and be ready with whatever tools you'll be using to persuade the faceplate off.....

Heat the faceplate only as quickly as you can till it's good and hot, then give it a whack, a tug or whatever force you will use.....the hot faceplate on the relatively cooler spindle just might help it loosen.....

Jim

Lew Hartswick
11-11-2007, 07:45 PM
I don't understand why the lathe manufacturers do not make a simple but safe spindle lock for this. All it would take is a hole in the appropriate location.

Thats an idea. Why not just drill a cross hole in the spindle?
...lew...

wierdscience
11-11-2007, 09:00 PM
Bolt a bar across the backplate,drill a dimple in the edge of the bar to help locate the tip of an air chiesel point.Lock the spindle with a strap wrench,put your weight into the air hammer and squeeze the trigger.Hold it down until it impacts off.

That trick has worked several times for me since most times a stuck chuck resulted from a long interupted cut being made which impacted the chuck tight in the first place.

DickDastardly40
11-12-2007, 06:09 AM
Is there a keyway anywhere on the shaft?

I made a split collar of the diameter of the shaft out of hex stock so it could be gripped in a vice and with a keyway to match the shaft. Can post photos later when home if required.

A little bit of leverage on the chuck followed by a pop and unscrewed nicely.

Al

sconisbee
11-12-2007, 02:44 PM
I've used two methods in the past, neither are exactly "textbook". However...

method 1) chuck up a bit of hex stock tight down on it then use an impact driver on the hex stock.

Method 2) find your biggest allen key like really big, or in this case as its a 4 jaw take some square bar bend in into an L shape making sure that the longer leg of the L will clear the lathe ways, then give the L shaped piece of metal downwards with the biggest hammer you have (assuming the bar is facing towards you) before you whack the metal make sure the lathe is not in backgear and nothing is locking the spindle... it may or may not work but is worth a try if nothing else works.....oh this trick works great with portable drill chucks that are threaded on.