# Quick change gearbox disassembly?



## WesPete66 (Mar 13, 2014)

With the warmer weather I can finally think about getting my TH54 up & running. I noticed when turning the chuck by hand there seems to be a noticeable drag whenever the lead screw reaches a certain rotation. I wonder if a gear/gears got crusted with dirt on the top side as it sat idle for many years(?). Also the two selector levers seem to be quite loose at their bases (is that common?). It works best to use two hands to move the levers side-side. So I'm thinking a disassembly is in order, to check things out..  I have the manual for the gearbox, but is there anything special to watch for when taking it off/apart? Is it timed to the spindle or drive gears in any special way? :thinking:

PS: A little surprise for me, I discovered this one has a power cross feed! I wasn't even aware my lathe had that. :allgood:


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## schor (Mar 13, 2014)

The loose selector levers probably means the bushings are shot. I have a qcgb with the same problem which I am going to rebuild.


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## wa5cab (Mar 14, 2014)

wespete66,

Atlas 10" machines with model numbers beginning with a letter are all 10F Series.  10F Series all have power cross feed.  The 10" without power cross feed all have 4-digit model numbers like "1042" or 4-digit + 1-letter like 1036C.

Robert D.



WesPete66 said:


> With the warmer weather I can finally think about getting my TH54 up & running. I noticed when turning the chuck by hand there seems to be a noticeable drag whenever the lead screw reaches a certain rotation. I wonder if a gear/gears got crusted with dirt on the top side as it sat idle for many years(?). Also the two selector levers seem to be quite loose at their bases (is that common?). It works best to use two hands to move the levers side-side. So I'm thinking a disassembly is in order, to check things out..  I have the manual for the gearbox, but is there anything special to watch for when taking it off/apart? Is it timed to the spindle or drive gears in any special way? :thinking:
> 
> PS: A little surprise for me, I discovered this one has a power cross feed! I wasn't even aware my lathe had that. :allgood:


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## WesPete66 (Mar 16, 2014)

OK, so I started taking the QCGB apart, and yes the selector lever bushings are badly worn.. 
The gear under each selector lever is apparently keyed to the shaft. So how does one get the key out of there to be able to pull the shaft out? What did I miss?
Wes


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## wa5cab (Mar 16, 2014)

Wes,

The only key in the QCGB (10" or 12") is in the main spindle (the one with beau coup gears on it).  The spindle that the two selector levers pivot on is retained by two collars and a groove pin.  The shafts that the two larger gears in the two levers run on are press fits in the levers.  You may need a copy of the 10F parts manual and the Craftsman 20140 manual.  The former for the correct part numbers and the latter because it is almost the same and is a much better quality copy. 

Robert D.


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## WesPete66 (Mar 19, 2014)

Well I think I'm about ready to buy some parts from Clausing, but am hesitating.. I'm not sure the QCGB shown in my literature is same as what's on my lathe & I don't want to buy a bunch of parts that don't fit my lathe. 
a. Is there a way to identify this QCGB?   (I have Lathe Bulletin 10L-6, of which the images match my parts but the print is not legible. I also have a Lathe Bulletin 10L-1500-2, which also appears to match my lathe & is what I plan to order from).
b. When I have a parts list made, how should I go about purchasing parts from Clausing?
Thanks again!
Wes


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## schor (Mar 19, 2014)

Got some picks? And maybe even casting part numbers, gear numbers, anything?


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## WesPete66 (Mar 19, 2014)

I believe that I have either a model 1500 or 1570 (but I can't find what the difference between the two is). The parts match the exploded iso drawing in bulletin 10L-1500-2 exactly. The levers are marked #10-1506, and the gear box housing is marked 10-1501.

I think I now know why the bushings are all worn so badly. After finishing dis-assembling it tonight, I was looking it over. I've been curious about how the oilers work. When looking at the bushing ID's, I noticed there is no hole to allow oil to flow through to the shaft. Am I right, should there be a hole drilled through the bushing?  I'm thinking a previous owner at some point replaced the bushings, but failed to drill the oil holes after pressing them in..


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## schor (Mar 19, 2014)

Yes, you want oil holes in the bushings. It is possible they are there but were never oiled and filled with crud.



WesPete66 said:


> I believe that I have either a model 1500 or 1570 (but I can't find what the difference between the two is). The parts match the exploded iso drawing in bulletin 10L-1500-2 exactly. The levers are marked #10-1506, and the gear box housing is marked 10-1501.
> 
> I think I now know why the bushings are all worn so badly. After finishing dis-assembling it tonight, I was looking it over. I've been curious about how the oilers work. When looking at the bushing ID's, I noticed there is no hole to allow oil to flow through to the shaft. Am I right, should there be a hole drilled through the bushing?  I'm thinking a previous owner at some point replaced the bushings, but failed to drill the oil holes after pressing them in..


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## wa5cab (Mar 20, 2014)

Wespete66,

QCGB Model 1500 is for lathes with 3/4" dia. lead screws.  1570 is for one with 5/8".  As you said earlier that yours has power cross feed, yours has a 3/4" so your GB is a 1500.

Robert D.


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## WesPete66 (Mar 25, 2014)

Yes, looks like it's the 1500. Called, ordered & rec'd bushings for it. (The sales person at Clausing was quite helpful)
Hmm, minor point I know, but before I go for the big vise-grips (not really), how does one remove those little oilers? Are they just press fit in place? threaded?
Thanks again!
Wes


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## schor (Mar 25, 2014)

Usually they are press fit. You can use the vise grips and just buy new ones.

How much were the bushings? I need some but was thinking on just making them myself.


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## WesPete66 (Mar 25, 2014)

Steve,
They weren't terrible. I ended up buying 15 bushings for $34 plus s/h if I remember right. One p/n was not available, and the big one was gonna be ~$11 so thought I'd try to find a cheaper one locally.. (shoulda just bought it because now I'm without & have to work to find one! :banghead: )
I asked prices for the two main shafts. They would have been ~ $60 & $75, so passed on those. Mine are kinda worn due to the oil hole thing, but will probably re-use them. They'd be an easy part to make with access to a mill..


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## iron man (Mar 25, 2014)

When I tore mine down I did not see a bushing in there you couldnt find at a menards or a fastenal. But there easy to make on your lathe even if the quick Change is not attached. Ray


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## Rob (Mar 26, 2014)

WesPete66 said:


> I think I now know why the bushings are all worn so badly. After finishing dis-assembling it tonight, I was looking it over. I've been curious about how the oilers work. When looking at the bushing ID's, I noticed there is no hole to allow oil to flow through to the shaft. Am I right, should there be a hole drilled through the bushing?  I'm thinking a previous owner at some point replaced the bushings, but failed to drill the oil holes after pressing them in..



The bushings are oil lite bushings. They are porous and do not need nor do you want oil holes drilled in them.


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## wa5cab (Mar 27, 2014)

Wes,

Your bushings were probably worn out because a PO never followed the lube instructions.  The oilers should be filled either daily or before every use, whichever is longer.  

And you definitely do not want to replace any of them with plain brass bushings.  You should also avoid buying generic bushings and machining them to fit.  The machining process will probably seal the surface and they won't oil properly.

Robert D.


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## iron man (Mar 27, 2014)

Lets face it Atlas did not have the market cornered on special bronze bushings what they used in the day was very very typical as what you find today just about everywhere. I spent a lifetime making bushings the oil-lite bushing are nothing but cast bronze ( powdered metal bronze ) heated up and quenched in oil when you machine it you can see the oil come out we use to make our own oil-lite bushings some now are just done with 30 weight oil and vacuum.. So you do all your machining before hand and then heat them and quench in oil or put in a container and apply vacuum and let them sit for a while very easy to do.

The surface will never seal because the bushing are cast and are very porous othewise you would not be able to impregnate them with oil ( thats why you have to keep oiling them oil-lite will run dry someday) and if they where not porous the shaft rubbing against them would seal the surface. Most store bought bushing are cast bronze and it is not hard to see the differance between brass and bronze. On the other hand you can use brass just drill your hole and keep it oiled brass is a very good bearing material it will out live you and the machine. Ray


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