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South bend 14-1/2 by 36-1/2 lathe

cub

Plastic
Joined
Jan 16, 2020
I am in the process of buying a South bend 14-1/2 by 36-1/2 lathe with a 6ft bed I need to know what year it was made and what hp the motor is All I know it has a 460v 3ph motor a 1ph rev/fwd drum switch As of now all I seen are pics of it and nowhere do I see a on/off switch or button I assume the drum switch turns it on or off? When I get this lathe I will change the 3ph motor to a 1ph motor of same hp The factory specs say it weighs 2250 lbs Is this correct? It has a 8 inch 3 jaw chuck on it now and comes with a 12 inch face plate What im needing most info about it is the year it was made and what hp the motor is The serial# is 143691 The cat# is 8183C My guess it was made in the 40s or 50s
 
Guessing that is close.

Do NOT change that motor unless you need to.

Ours is 240 vac 3 phase 2 hp and we put an Allen Bradley 3 HP VFD on it.

We modified the drum switch so it controls "run" "stop" and "reverse".

We stripped the jumpers then bent the tabs on one so that they always "make" before the others and the stop is connected there.

Drum switch controls vfd and with a 2 hp motor and back gear we have both RPM and MPR with plenty of torque.

Plus no messing with different motor.

Get a camera under the motor and get photos of the data plate to see if it can be rewired to 220/240

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why not change the motor to a 1ph motor? to keep it original? if so. I don't mind changing it from how ''original'' or ''oem'' it was Its not that I ''need' to change it Its I ''want'' to change it I have learned by experience that changing a motor is much easier than trying to figure how a vfd is programmed or set up nobody knows how to set a vfd up I even have a rotary phase converter but don't want to be switching on/off something extra to start a lathe Also why didn't SB use a on/off power switch? here u are reaching over a spinning moving chuck or part to turn on/off a machine by a drum switch located behind/above the chuck or spinning item in the chuck, why? to me this isn't safe This is like reaching over and behind a spinning saw blade on a table saw to turn on/off a table saw Also I still want to know the year this lathe was made no guessing
 
We added a foot bar to add a stop function to ours so no need to reach over the work.

Not changing motor was not to keep original but rather lazy and cheap

The 14.5 was more toward commercial rather than homeowner and as such the motor is a good quality unit.

It already is in place and aligned and matched to the machine.

An equal quality motor would have cost more than the VFD and required a lot more work to install.

We have infinite variable speed with the turn of a knob and seldom move a belt.

Did ours 6 years or so ago and posted a thread showing how it was built

The VFD is mounted in an enclosure attached to a subframe that includes the foot switch bar that attaches to the bottom bolts under the chip tray

Looks factory.

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vfd for south bend lathe

then I assume your vfd has a display that shows rpm? If so, then this would be a improvement How much did your vfd cost Also, what do u mean by a ''quality'' motor? sometimes a older machine will use a older ''u'' frame type motor that the mounting bolt pattern and shaft size is different than a modern nema frame motor Sounds like a vfd is like a rheostat When I change any 3ph motor to a 1ph I usually update the off/on switch or add a off/on push button square D switch Now, if a machine needs or uses anything bigger that a 1 hp motor it gets a magnetic switch too Most 1ph motors I use are tefc type motors made in USA What type of frame does a SB lathe use? When u installed the vfd did u bypass the fwd/rev drum switch? BTW what is a ''fair'' price to give for a 14.5x36.5 SB lathe that is complete not rusty or missing parts or repair?
 
Lots of old lathes have the reversing drum switch located where you had to reach over machine to operate it, I've used many like that, maybe not the safest, but never sucked me in either. You can move the switch if you so desire. The reversing drum switch IS the power switch, why would you want another one?

The only real downside to a 1ph motor is the centrifugal switch, if you want to run in highest speed, if you put too much load on motor it will slow enough to let centrifugal switch disengage and motor goes back to start winding, then run, then back to start, it plays hell on your cut and all the lights will flicker.
 
I guess the idea of reaching over a spinning chuck or part to me isn't the safest idea to turn off/on a lathe Sure it is ok because 1000s of times before and no accident happened but it takes only ''one'' time and after that, its too late Anyone know when or if SB discontinued locating the drum switch or on/off switch behind the chuck to a safer place? And yes, relocating the drum switch to a better place im willing to do Being I don't see any other type of on/off switch on this SB lathe I surmised the drum switch was the on/off switch I suppose relocating the drum switch under the chip pan easy to get to would work BTW how often does the reverse get used on a lathe? As for if u plan to do heavy work at high speeds loads on a 1`ph motor then u should get at least a motor 1hp larger like a 3 or 5hp and u wont be having problems overloading or over heating a 1ph motor As a example, if your lathe uses a 3ph 2hp motor now and u change it to a 1ph motor then get a 3hp 1ph motor instead to be sure there wont be overloading a motor of less hp at high speeds doing heavy cuts I suppose a drum switch is like a transfer switch for a power generator with 2 ''on'' positions and the center a neutral or a ''off' position
 
My old lathe had a 1/2hp motor originally, I replaced it with a 1.5hp 1ph motor, and still had problem with centrifugal switch at high rpm with a load, my choice was lighter cuts, or slow down spindle for some gear reduction. There was no room for anything larger.

You can relocate switch to where ever feels safe to you, but if you have little ones in shop, you might want to consider what they can reach too, and don't leave the chuck key in the chuck! If you want to really saftiefy it, put a disconnect on wall behind lathe that you can padlock in off position.

Edit: You can cut lefthand threads running in forward rotation, not sure what you mean by toolpost and cutting tool being backwards???????
 
did it originally come with the 1.5 hp 1ph from the factory or was it changed by a previous owner? What frame size and brand motor is it?
 
did u use the same size factory pulley the 1/2hp used on the 1-1/2hp motor u replaced it with?
 
well, if u look at where the motor sits on a SB lathe like the one im getting,, it looks like there is well enough room inside that the capacitors on a 1Ph motor wont be a problem if its a nema frame motor like a 56 frame But till I get this lathe I wont know till I do some measuring
 
well, if u look at where the motor sits on a SB lathe like the one im getting

So would that be an under-mount, rear-mount, or old line shaft machine with an over-mount motor, your pictures are not clear enough to see:toetap:

Sounds like you've got it figured out, slap a 5hp dual voltage, wired for 110v, motor on it and you can run it off a 50' extension cord anywhere in the garage.
 
Here are some photos from ours.

The Allen Bradley VFD has a 20 ma loop control output for controlling external devices.

It can be programmed to output based on load or frequency and we have ours set to frequency (relative).

The knob is 10k put for speed control.

It goes from full stop to quite a bit faster, been too long and cannot remember actual numbers.

The VFD was 200.00 on eBay and the enclosure was 30.00 at tye motor shop salvage yard and the ancillary materials were leftover parts and scrap.

We did need to stop by past employer to pick up a valve spring for the foot pedal return.

All of the VFD, control and foot switch is mounted on a sub frame that attaches to the bolts that protrude through the bottom of the chip tray.

We have have other lathes with single phase motor, works okay but limited to fixed speeds (not many) and would never convert 3 to 1 unless no other option.

VFD are too cheap to do otherwise.


The toggle switch is a 2p2p 20 amp light switch as main 240 vac power in.

On the drum switch we added a 240 vac neon pilot so we know mains are on.

The foot bar is in series with the stop loop.

We think ours is 2 hp, could be 1.5, need to hunt down our notes.

Have not stalled it yet, belt slip yes motor stall no.

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