Atlas/Craftsman 12x36" lathe...questions

Jason280 said:
I looked through a few FB marketplace ads, and found a cheap treadmill for sale...but wasn't really convinced the motor would be big enough. I guess I need to do a little more research.
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Most treadmill motors are in the 1.5 to 2.5 horse range. But it is easy enough to look it up if you know the make/model of the treadmill.
 
Keep on eye on CL for used motors - many can be had for $20-40, maybe consider a 3 phase and get a cheap VFD

I had a worn chuck like that on my SB9A, served me well for years. If you can make your part in one chucking runout doesn't matter.

Consider making an ER collet chuck for better runout than any chuck. I made both er25 and er32 chucks that are dead on. You could also buy an er chuck with an MT3 shaft (I think yours is MT3?) but you would not have thru hole ability.
 
Most treadmill motors are in the 1.5 to 2.5 horse range
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I know most are physically smaller than comparable electric/AC motors, but can they truly match torque & HP levels of the AC motors? I assume they are all DC motors, but honestly not sure.
 
Jason280 said:
I know most are physically smaller than comparable electric/AC motors, but can they truly match torque & HP levels of the AC motors? I assume they are all DC motors, but honestly not sure.
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I have a couple but never used them to power the lathe. I have used them to power the leadscrew so I don't have to listen to noisy gears. It so quick and easy to change speeds with the belt I don't need variable speed. . They definitely lose torque at the lower rpm's but if you retain the countershaft it shouldn't be an issue. I made my own controller similar to this:
Didn't need the coil though.
 
Even if you don't need variable speed, the starting torque of a DC motor is quite incredible. Only real downside is the electronics needed to power them as treadmill motors are brushless and therefore can't just be fed straight DC.
 
It would be easy to simply keep the electronics of the treadmill, though....just seems like it might be more work than it is worth.
 
The parts needed to make your own controller are approx $10 on ebay and take 15 mins to put together. I used the treadmill controller for a while but it's huge and offers less speed control.
 
OK. But if it were mine, I would want to know why the GB output shaft had over 1/4" of endfloat before I used the thing any significant amount.
 
Not sure if I'd call it "endfloat", it only exists once the support bearing at the end of the table is unbolted. In other words, its correctly staying in position while assembled, its simply not wanting to slide out of the QCGB...at least, its only sliding 1/4" before stopping.
 
The only reason that on your machine, the right lead screw bearing controls the end float of the gearbox output shaft is that your lead screw is frozen at its current position in the output shaft. It should not be. Removing the two bolts attaching the bearing to the bed should have allowed you to easily remove the lead screw from the lathe. Remember that when everything is working, moving the output shaft also moves the gear on the other end of it. And 1/4" of movement of the gear will disengage that much of the gear teeth. Which cannot be good.
 
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