Quick change gearbox disassembly?

[WesPete66]

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:

 

[schor]

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

 

[wa5cab]

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.

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:

 

[WesPete66]

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

 

[wa5cab]

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.

 

[WesPete66]

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

 

[schor]

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

 

[WesPete66]

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..

 

[schor]

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

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..

 

[wa5cab]

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.