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Replacement Motor For South Bend 9 inch lathe

jearnhart22

Plastic
Joined
Mar 31, 2020
Hello,

I am looking to replace the GE motor that came with my old South Bend Lathe. It is a single-phase, 3.8 amp, 115 volt motor at a 1/4 HP w/ a capacitor. I would like to upgrade to 1/2 HP. I am using form cutters to cut into the tailstock side of the workpiece... I think a 1/2 HP should be enough but if anyone has any opinions I'd like to hear them. Does anyone have suggestions on a new motor?
 
Stick a 1-hp 3-phase motor with a VFD on it. Bye bye belt changes, in large part. That's what my Dad did with his 9" Model A. Just don't be too tempted to run at above rated speed without making sure the spindle bearing clearance is loosened up and the oil supply is working. Pay close attention to the bearing temperature. DAMHIKT (more like don't ask me how my Dad found that out).
 
It is my understanding that if the intent is to underspeed/overspeed the motor needs to be rated for inverter duty, or risk burning up the wiring insulation.

These typically cost more than a typical 3 phase motor. I set mine up with a 1 hp, and still belt shift- but I find adjusting the frequency is a great way to tweak up/down the rpms to get a better finish, optimal chips, esp when turning- easy to increase SFM as the diameter reduces.
 
QT: [think a 1/2 HP should be enough ]
1/2 OK and a 3/4 would not hurt. I would choose a motor of the same frame perhaps it is a 56? and sealed motor that looks nice with not crimping space. I think the machine has enough speed selections,I see ok motors in that range from about $60 to $304.

Mostly turn to the tighten the chuck direction with any motor choice.


$60 new old stock...Yes if you can use 3PH
3ph 3/4 cppy paste this to an ebay search-> Dayton 3 Phase AC Motor 3/4 hp 1725 rpm 60 cyc 1425rpm 50cyc Old Stock/New !
 
tobnpr,

This risk topic comes up about once a week on PM. I run several antique motors off of VFDs, and have never had an issue. I have never heard of anyone else having an issue, either. Jearnhart22 does not need to buy an inverter duty motor.

RKlopp
 
1/4 Hp is a little light for my tastes....BUT if you have not done it already you can make a significant gain in power TRANSMISSION by using an automotive poly v belt..aka- serpentine belt.

a J section 6 rib of whatever length you need will make a big diff.

10-15 bucks just might do ya, and even if not youll still want to do it anyway if you goal is more power to the spindle.
 








 
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