Gear slipping on my 10k - Practical Machinist - Largest Manufacturing Technology Forum on the Web

jasono · #1 09-28-2009, 12:58 PM

Hello
Iam a newbie
so please bear with me when it comes to my explanations,so i rebuilt my 10k from a pile of scrap and i have a problem where i select the A and B settings on my gearbox the 20t gear and the idler gear slip and make this horrific noise, the C D E settings thread fine can anyone offer any help with this matter,also i bought this gearbox off of ebay the gears and operation
are fine it seems to be in good shape (no broken teeth all moving parts operational)
thanks in advance
J

aametalmaster · #2 09-28-2009, 06:29 PM

Is everything installed right and no broken woodruff keys anywhere inside? ...Bob
http://www.wswells.com/partslist/903E.pdf

tommied · #3 09-29-2009, 05:24 AM

I had this one time and had to tear down gearbox and clean oil passages out, put new felt and lightly sanded the shift shaft just to smooth it. The bottom shaft wasn't oiling causing it to bind. hope this helps. tommie

tjwal · #4 09-29-2009, 08:31 AM

With the gearbox set at 20tpi can you turn it by hand?
IIRC at 20 tpi the gearbox ratio is about 1:1 so it should turn fairly easily.

JohnW

tjwal · #5 09-29-2009, 08:39 AM

I should have read the original message more carefully . The same sort of questions though.

What tpi setting is causing the problem? Can you turn it over by hand or is it locked up?
Does it happen even with the half nuts open?

JohnW

Quote:

Originally Posted by tjwal

With the gearbox set at 20tpi can you turn it by hand?
IIRC at 20 tpi the gearbox ratio is about 1:1 so it should turn fairly easily.

JohnW

jasono · #6 09-30-2009, 04:22 PM

it will turn maybe 3 revoulutions and then lock up and slip any tpi on the a or b setting
just checked the key in the shaft where the 20t gear is i thought it was worn but i have found that it is back in the key(there is a space about an 8th of an inch at the front of the way) way should it be at the front of the way?
thanks for all your input
Jason

jasono · #7 10-08-2009, 02:10 PM

ok so i have taken off the gearbox and cleaned it was pretty dirty put it back on and the same problem i used fresh oil.it can only be the gearbox as i have eliminated all other possibilites i am at the point where i am going to part it out but really dont want to as these are lovely lathes, i tried contacting south bend company they had no idea where to start or what to do so maybe someone out there can help me? i have a gearbox that came in the scrapheap without the bottom shaft or tumblers i was going to pull this down to try and get some idea how to pull down the complete one
thanks for your help in advance
Jason

promacjoe · #8 10-08-2009, 03:42 PM

Let me explain how the gearbox works and maybe you can get an idea of what is wrong.
First you will need a copy of the parts list. I recommend using the one from the Department of the Army for the South Bend lathe document number "TM 9-3416-235-14&P".
Note: this document says 9 inch lathe but it is for both the 9 inch and 10K.
I believe this document is available from "http://www.wswells.com/index.html", if not you can use one of the other documents posted there, specifically document page 903E.

Find the parts list for the gearbox. At the top you will see the input shaft, there are four gears on this shaft set up as compound gears, one of which is keyed to the shaft. That is 1 large gear connected to 1 small gear. These gears are connected using small pins on opposite sides of the gear. If these pins are missing or broken it could cause your problem.

The opposite gears have a similar setup but are not keyed to the shaft.
One gear by itself and to compound gears, connected using the same method

Note: if you remove these gears make sure you get them back in the same order, any deviation could cause serious problems.

The tumbler gears ride against these gears and transmit the power through a second gear which is connected using a double key made into the gear. These keys can be sheared off of the gear. This would also cause your problem.

The next set of gears are all keyed to the shaft and are arranged from smallest to largest. These gears also have a pin that runs through most of the gears, this just adds additional stress relief and helps to apply an even force throughout all of the gears regardless of gear setting. It is doubtful that these gears would be sheared unless the spin is not there, But it is worth looking at.

The last gear is on the output shaft this year can be turned backwards. This gear has a predominant shoulder on one side the shoulders should be against the nut. If this gear is turned backwards it could cause your problem. But you would probably see small pieces of gears come tumbling out of your gearbox.

I hope this helps.

promacjoe

PS. I looked on the www.wswells.com website and found the Army document listed under data and information/1980 Army Maintenance and Repair Parts, Model CL670Z. This document has a lot more than just the basic parts list.

Hope this helps.

jasono · #9 10-08-2009, 06:55 PM

thanks Promacjoe
ill let you know how it goes i have the army manual as well now i have more info from www.wswells.com
ill be in touch
regards
Jason

jasono · #10 10-12-2009, 04:04 PM

Ok so i went into the gearbox and pulled out the bottom shaft cleaned it,cleaned out the whole box the other gears are working fine and look great when i put back in the other shaft it was extremely hard to move the gears, i lubricated everything and and was turning great
it ran perfect for about 10 minutes going through the different positions A B C etc
and then all of a sudden it started locking up again all the while i was oiling the gearbox making sure all was good.
i am wondering also about the forward and reverse selector,just before it locked up i stopped the machine selected reverse and could not get it to move with out turning the pully by hand
could this be adjustment by making the idler gear to close up against it?
also i find that the same selector is very easy to come out of its horizontal position.
thanks for your thoughts
regards
Jason

jasono · #11 10-19-2009, 03:55 PM

Can any one offer any advice id really appreciate some help
thanks
Jason

Joe Carroll · #12 10-19-2009, 05:04 PM

Hang in there. These guys will get you through it.

tommied · #13 10-19-2009, 05:36 PM

Will it turn if you take shifters out to neutral, then try the abc one then the other. Its straightforward to troubleshoot by eliminating each gear or shaft one at a time. Hang in there I had to take mine down twice before I got it to freewheel. Sometimes the gears in the shifter itself will gall. You have us all wishing we could hold the gearbox and examine it for you. Take while shifters are out of gear, can you turn the lead screw easily? Just some thoughts. tommie

The Energy Rebel · #14 10-19-2009, 06:12 PM

Quote:

Originally Posted by jasono

Ok so i went into the gearbox and pulled out the bottom shaft cleaned it,cleaned out the whole box the other gears are working fine and look great when i put back in the other shaft it was extremely hard to move the gears, i lubricated everything and and was turning great
it ran perfect for about 10 minutes going through the different positions A B C etc
and then all of a sudden it started locking up again all the while i was oiling the gearbox making sure all was good.
i am wondering also about the forward and reverse selector,just before it locked up i stopped the machine selected reverse and could not get it to move with out turning the pully by hand
could this be adjustment by making the idler gear to close up against it?
also i find that the same selector is very easy to come out of its horizontal position.
thanks for your thoughts
regards
Jason

Hey J,
Haven't read thru all posts but I thought I may have some words of encouragement.
Don't scrap anything,yet.
I don't have a 10K , but an Atlas. Got it out of an old garage. The last thing I got to work was the gearbox and leadscrew. It took a lot of time and a LOT of oil. They're right when they say it should turn by hand. Disengage the gear select pins and the carriage lever and watch your fingers!
I finally took out the 2 bolts on the end of the leadscrew (far right), pulled it out, cleaned and oiled everything and "bumped" the motor (all in back gears) and finally put it all back.
It did the same thing you described. worked for a few and jammed up.

So I did it again............and maybe one more time.

Moral?
It's purring fine now.
Just keep at it.

Forgot to tell you when you pull out the leadscrew, you take the carriage off, sliding it all the way off the ways.
When you do, turn it upside down and look for the beveled gear that drives it. That gear has a nut on the top of carriage that if you loosen 1/2 turn, it might just unbind the leadscrew if it is turning otherwise.
I think that was the final trick that got mine right.

jasono · #15 10-20-2009, 05:24 AM

Guys thanks for the encouragement,i have tried realeasing the same nut on the apron lock
that makes no difference but what im finding is that i will turn the lathe by hand the opposite direction take the forward reverse selector out of gear put it back in again without moving the gearbox and it will run again then lock up again,now something i also noticed is that at the end of the leadscrew there is a collar a washer and then a nut is this correct,because someone said to me that they just have on a nut.the gearbox moves freely when fully disenguaged?
ill keep trying, ill try turning the leadscrew today Tommie
thanks
Jason

The Energy Rebel · #16 10-20-2009, 06:24 AM

Quote:

Originally Posted by jasono

now something i also noticed is that at the end of the leadscrew there is a collar a washer and then a nut is this correct,because someone said to me that they just have on a nut.the gearbox moves freely when fully disenguaged?
ill keep trying, ill try turning the leadscrew today Tommie
thanks
Jason

Yes.
And yes on the gearbox ? too.
I wish I had taken pics of mine taken apart when I went thru this, but oh well.
What I did was remove carriage and leadscrew and make sure everything in gearbox ran for a while without any binding. Then I knew that the problem was not there. When you do this, you should see all 3 bushings (holes) in the gear box turning when the gears are selected by the pins. 2 on the bottom and 1 on the top that the leadscrew goes into.
Again, it took a lot of oil and babying it before it got to that point.
Then the only thing left that could be causing the "bind" was the leadscrew. I loosened up a few nuts (and more oil) and voila!
Just go step by step and keep everything a little "sloppy" until you get it unbound so you don't break any gear teeth. Better to slip than break.

jasono · #17 10-21-2009, 04:30 PM

ok so i tried to turn the leadscrew and it does the same thing it tuns for a bit and then tightens up so im guessing that that is my problem and i need to loosen it up a bit and try that i will also try what energy rebel suggested by removing the leadscrew and try running the gearbox.
jason

jasono · #18 10-25-2009, 10:07 AM

ok so its definately the gearboxeven when i have the levers disenguaged the gearbox locks up
so back in the box i go
any thougts anyone?

jasono · #19 10-25-2009, 10:17 AM

the energy rebel
i answered the pm but you have them turned off
Jason

jasono · #20 11-03-2009, 11:21 AM

ok so i cleaned the gearbox pulled it down put it back up fond a bit of damaage on the selector shaft in the oil ways filed it down the gearbox is running perfect then i put it back up
ran it perfect no problems put back on the leadscrew and it locks up again i am @ a loss
any more ideas would be really appreciated im a newbie and just want to use this wonderful lathe