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Atlas 4804 something bent or wrong

kc0dwx

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#1
So a few months back I purchased an atlas 4804, which as I understand is a Clausing lathe. At 12" there is probably .010 inch or more runout. Something that is very visible, might be more then I'm claiming. This is with the 3 jaw chuck. I have also a 4 ja2 and a face plate but have been unable to get the 3 jaw off. So is the small chuck the problem or do I have a bent spindle?

I have checked that the run out is not the stock but rather the chuck by rotating the stock. All bearings feel tight with no play. Run out is less at chuck then 12" or more out by a long shot.

I've tried using hex stock with a cheap air impact wrench to get the chuck off so I could try the drill chuck or 4 jaw but that hasn't worked as I've been unable to break the chuck loose.

I'm guessing somebody crashed this at some point however I can find no other signs of damage. Maybe(I hope) this is just a really crappy chuck.
 

Bob Korves

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#2
To measure the spindle runout you must measure the spindle runout, not the chuck runout. You will need to get the chuck off before you can do that. Measuring one thing to check another is confusing and hopeless. Accuracy checks should be done in as simple a way as possible that gives good results. Stacking tolerances tells you nothing useful.
 

GarageGuy

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#3
It is much more likely that the jaws or scroll on your 3-jaw chuck are worn. 3-jaws are not all that accurate to begin with, so .010" runout at 12" out doesn't sound crazy at all. I would bet that doing the same test with a 4-jaw or collet chuck would yield much better results.

I feel your pain. My first lathe, a Logan 10", came with the chuck stuck. The previous owner had used it for turning wood. :eek 2: I used lots of penetrating oil and a heat gun on the chuck to finally get it loose. After I got it off, I found sawdust and traces of wood glue inside. :mad:

GG
 

Bob Korves

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#4
Don't use the back gears to stop the spindle from turning while you pound on the chuck or use a big wrench to get it off. Don't pound on it at all. Go easy and with patience. It probably took many years to get stuck like that. You can spend a few weeks working at getting it off if necessary. Gears prefer to have all their teeth... Be kind to your machines and they will be kind to you...
 

willthedancer

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#5
You can test the spindle by opening up the chuck, cleaning the spindle taper, and putting a shell reamer arbor in it. Then you'll know whether it's the spindle. I have a spare spindle that will come available sometime in the next couple of weeks btw. It isn't perfect, but it will run.

If your machine is original, you have an indexing hole at 9 o'clock from the chuck. That may be a way to get the spindle held enough to get the chuck off. Penetrant from the inside may help too.
 

kc0dwx

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#6
It is much more likely that the jaws or scroll on your 3-jaw chuck are worn. 3-jaws are not all that accurate to begin with, so .010" runout at 12" out doesn't sound crazy at all. I would bet that doing the same test with a 4-jaw or collet chuck would yield much better results.

I feel your pain. My first lathe, a Logan 10", came with the chuck stuck. The previous owner had used it for turning wood. :eek 2: I used lots of penetrating oil and a heat gun on the chuck to finally get it loose. After I got it off, I found sawdust and traces of wood glue inside. :mad:

GG

Sorry it is more like .1" at 12" It is crazy visible to the naked eye. I don't recall the exact amount but it was a lot. I'm still hoping it is something with the chuck however.
 

kc0dwx

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#7
Don't use the back gears to stop the spindle from turning while you pound on the chuck or use a big wrench to get it off. Don't pound on it at all. Go easy and with patience. It probably took many years to get stuck like that. You can spend a few weeks working at getting it off if necessary. Gears prefer to have all their teeth... Be kind to your machines and they will be kind to you...
Yes I realize you shouldn't use the back gear to stop it. What bad is that is exactly what the manual says to do. I have basically been using a cheap air impact wrench with 7/8 hex stock at about 12" long so just the stock is absorbing a great deal of the shock... Been holding the spindle with both the drive motor and belt an/or a rubber strap wrench. I figure the rubber will give long before a gear or pully.
 

willthedancer

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#8
Yes I realize you shouldn't use the back gear to stop it. What bad is that is exactly what the manual says to do. I have basically been using a cheap air impact wrench with 7/8 hex stock at about 12" long so just the stock is absorbing a great deal of the shock... Been holding the spindle with both the drive motor and belt an/or a rubber strap wrench. I figure the rubber will give long before a gear or pully.
Your chuck is soaking up the impact forces via inertia.

Consider making up or buying a split collar an putting it in place of the first change gear. You can destroy a split collar and not hurt the spindle.

Sent from my Moto G Play using Tapatalk
 

Bob Korves

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#9
Yes I realize you shouldn't use the back gear to stop it. What bad is that is exactly what the manual says to do. I have basically been using a cheap air impact wrench with 7/8 hex stock at about 12" long so just the stock is absorbing a great deal of the shock... Been holding the spindle with both the drive motor and belt an/or a rubber strap wrench. I figure the rubber will give long before a gear or pully.
The manual assumes that the chuck will come off easily, like all the new ones on new factory lathes did... Those old Zamak gears and other parts are fairly delicate as well. They never thought those lathes would still be in service after all this time, and after sometimes decades of neglect. Work some penetrating oil into all the access places for the spindle threads and register. Turn it toward loose, then toward tighter, more penetrant, repeat at intervals. Time and patience helps a lot. Eventually they just spin free.
 

kc0dwx

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#10
The manual assumes that the chuck will come off easily, like all the new ones on new factory lathes did... Those old Zamak gears and other parts are fairly delicate as well. They never thought those lathes would still be in service after all this time, and after sometimes decades of neglect. Work some penetrating oil into all the access places for the spindle threads and register. Turn it toward loose, then toward tighter, more penetrant, repeat at intervals. Time and patience helps a lot. Eventually they just spin free.

Pretty much my approach so far penetrating oil loosen, tighten and walk away without get mad. I'm not a machinist by trade by any means. My dad is and he has both a Swedish or Swiss large lathe as well as a large milling machine that does both horizontal and vertical setups both 3 phase machines, so I've become interested and hate asking him questions that make me look like an idiot and he isn't really capable of coming to location to help anymore.

I started with a very small atlas a couple years back and have used it very successfully. I've even done some work for my place of work.

Much can be accomplished and learned with patience.
 

Silverbullet

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#11
If the spindle is protruding out the back you can make an easy clamp . A piece of hardwood ,,, oak ash or heart pine ,, drill a hole the size of your spindle in a piece about 2"# 6" then cut the board in two the long way ,then cut an extra 1/4" off , drill to holes for bolts to tighten it add a piece of angle iron 2' long with holes drilled to mate with the board tighten them to the spindle. Then you can put plenty of pressure to release the chuck. It's the way we take barrels off of guns . Believe me your chuck will move and no damage to your spindle.
 

Bob Korves

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#12
(snip)My dad is and he has both a Swedish or Swiss large lathe as well as a large milling machine that does both horizontal and vertical setups both 3 phase machines, so I've become interested and hate asking him questions that make me look like an idiot and he isn't really capable of coming to location to help anymore.(snip
Lack of experience does not make an idiot, only someone who needs practice, study, advice, and help. All of those will help to change the equation toward experienced competence. Every one of us here was once a total beginner...
 

ewkearns

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#13
Do NOT use an impact wrench. Use a steady pressure... using a cheater bar, if necessary. Mix up 50%/50% of acetone and ATF.... that is the best penetrating oil you can find..... apply daily for a week or so. Then apply heat with a heat gun (NOT A TORCH) to the chuck..... just too hot to touch is as far as you should go. Try the cheater bar. If no joy, continue with the penetrating oil and take more time... Be patient and think this thing through. You've got a really good piece of machinery, don't screw it up!
 

markba633csi

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#14
The factory assumes the chuck isn't stuck THAT BAD, that's why they say to use the backgears. We know better. See above.
MS
 

ghostdncr

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#15
In this post on another thread, I relayed the story of separating a very large chuck/spindle arrangement prior to rebuilding: http://www.hobby-machinist.com/threads/16-von-wyck-machine

I remember working on an ancient lathe nearly forty years ago that had a threaded-spindle chuck frozen in place. I'm thinking it was a big old LeBlond. The guy that was rebuilding the lathe made up an interesting arrangement to wrench the chuck free of the spindle.

He took two pieces of 2" x 4" or 2" x 6" CRS and drilled and tapped two big bolts (5/8 or 3/4") in the steel pieces aligned edge to edge. Two washers were slipped between the blocks and the bolts were inserted and tightened. Then a hole was bored through about 1/4" bigger in diameter than the machine's spindle. The chuck was laid face down on the shop floor with the spindle pointing straight up and this "wrench" was bolted in place around the spindle and blocked up to be level and approximately centered. The washers were still in place as spacers between the two halves. A small pot of lead was melted and then poured into the gap between the wrench and the spindle and then everything was disassembled and the lead ring was cut into halves with a small piece of sharpened brass bar stock.

You know that tough, sticky sap that runs out of pine and cedar trees? The old guy had a coffee can with a pretty good collection of the stuff. He heated some of that on a stick and smeared a little on the spindle and the bore of the wrench caps before popping the lead back in and reassembling the wrench onto the spindle without the washers separating the two halves. The bolts were then tightened until they smoked and then about a quarter turn past that that!

The big 4-jaw chuck was clamped down onto another piece of thick wall tubing lying across its face. A couple of shop rags were wrapped around the spindle's journal areas and a larger pipe was slid up over it, with the pipe being probably 8-10' long. Another pipe was slid onto the 2 x 2" tube welded to the wrench's lower cap. With a man standing on each pipe about midways along their length, the old guy mounted the piece of tubing clamped into the chuck. It sounded like a .22 rifle firing when that chuck broke loose, or at least that's how I remember it.

To help my rambling make sense, below are a couple of sketches I banged out with hopes of tying things together. First, how the wrench was configured and bolted to the spindle. Second, a combined overhead and side view, with the three football shapes representing the mens' positions while breaking the chuck free. I hope the Von Wyck doesn't require anything this aggressive but if it does...
 
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