Repowering a 1916 Southbend Lathe

R

RobertHaas

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My old Lathe is in need of more power and I am unaware of how much power I can bring on board or how much the belts can handle.

I was thinking along the lines of a 3 HP single phase 220 motor.


Will I kill it with that?
 
You don't say what size the lathe is, but you would be hard put to use that much power on most any belt drive lathe; the motor won't kill it, the speed and cutting forces are what can cause undue wear and tear.
 
I think a 3 hp motor would be more than overkill for all but the largest South Bend machines. The 16" to 24" "precision tool room" machines came with a 3 hp motor. The 13" machines came with a 1 1/2hp motor, and the 10" machines came with a 1 hp motor. The 10" K series came with either a 1/2 hp or 3/4 hp motor, and the 9" machines came with a 1/2 hp motor.

Having said that I repowered a 1916 Seneca Falls Star #20 lathe (10"x60") with a 1 1/2 hp 1725 rpm motor. It's way more power than the machine can handle, but it was the best physical fit for the machine at the time. I do not fully tension the flat belt to avoid damaging something should I have a crash

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I would have turned the motor around under the countershaft to avoid chips and crud, or even put the vee pulley on the other end of the countershaft to keep chips and oil from getting caught in the belt and pulleys.
 
Surprisingly I rarely get chips and oil on the motor. Every once in a while there are a few chips on the mounting plate, but they're few and far between. The spindle max speed is about 600 rpm so it doesn't throw that much stuff around.

I do like your idea however. The machine no longer resides in this location, and the new location doesn't lend itself well to the motor being in it's current position. As luck would have it in the new location the motor is directly under the drain valves for the water lines to the sink in the garage. Every spring when I turn on the water I have to climb over the motor. In addition I have to be sure the lines are fully drained in the fall when I turn them off or they will drain on the motor. Fortunately it's a TEFC motor. However it's not a washdown motor.
 
I have a somewhat similar Monarch 9" lathe, and was fortunate to have it come to me with the original countershaft for overhead (lineshaft) drive, so that is the way it is set up, with a short lineshaft, motor overhead and clutches on the countershaft for forward and reverse operation. I am presently building a 12" swing long bed wood lathe, the drive system will be similar to what you show, but the countershaft behind the headstock will be pivoted off the legs, sort of lie was done on South Bend bench lathes, but with the motor below on a plate that is also on the same pivot system. This project is waiting for warmer nicer weather; here in Ca. we are spoiled, I have to admit, knowing your location!
 
The one in the attached pictures and those above was the one my wife's grandfather operated for over 40 years making prototypes for a vending machine company. When he retired it was given to him as a retirement present. On his passing it went to my wife's father. He used it for another 25 years for both wood and metal. When her father passed I inherited it. It's been in my shop another 20 years.


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Sorry, it is a 12" gap bed with a 72" bed.

Currently has a 1/2HP 120 volt motor, I am going to build a new platform and move the motor spindle up on top to make it an overhead design.
 
Yes, clearly underpowered! I think 1 1/2 or 2 hp would be plenty. There is one of those 16" gap bed SBs around here as well, but with I think an 10ft or longer bed length, it was converted from lineshaft drive a long time ago, but still uses one of the countershaft clutches.
 
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