running a 3 phase motor on a 9" South Bend

Hello
Please forgive me if I'm not on the good forum.
I am trying to find out if a 3/4 hp 1725 rpm triphase 208-220/440 volts motor is too much for my fine little South Bend.
I'm not into production work in any sort, I use it mainly for modeling jobs, hobby parts.
It is just that, pleasure of a retired old man.
This motor is available (old/new stock) at a very decent price.
I have had this fantasy, to try and run a VFD, again this is no power trip.
I could use 120 or 240 Volts AC 60hz. as input voltage,(canadian household voltage) but I am not sure this would provide a suitable output voltage to run that kind of voltage on this motor.
Your thoughts and comments, will help me quite a lot
Thank you and have a nice day.
Pierre

I see no reason not to.

The only issue is that you may not be able to get all the power through the flat belt system at all speeds, which at the lower end of the speed range is only really good for about 1/3 HP at reasonable belt tensions. At middle speeds you may be able to do better.

The 1" belt is capable of 1 HP, but that takes about 1000 ft/min belt speed, IIRC, which the pulley system does not allow at all speeds.

A rubber and canvas belt will stand more tension than a leather one, and will allow maybe 50% more power (actually belt tension).

Ther are VFDs which take in 120V single phase and output 240V 3 phase, as well as ones that do the same with 240V single phase input.

I briefly owned a 9" South Bend so I can offer some free advice, which is by definition worthless.

A weak spot is the spindle running in the cast iron headstock, no bronze bushing, even. Keeping it lubricated is crucial. At the beginning of the day, check the oil cups and fill them, then turn the spindle a couple of turns to distribute the oil. Of course, you are a victim of the previous owners. Check the clearance by putting a dial indicator on the top od the spindle and prying the spindle up. There should only be a few thousandths movement.

I used Mobil DTE 24 on my 14 1/2" South Bend and the bearings only wore about 1/2 thousandth in 40 years

Assuming it is in good enough shape to warrant the investment, get a 1/2" steel plate large enough to mount the lathe and motor assembly and bolt everything to it with shims to take any twist out of the bed. These machines were made down to a price and they skimped on iron. The improvement with the extra base is remarkable.

Bill

JST said:

I see no reason not to.

The only issue is that you may not be able to get all the power through the flat belt system at all speeds, which at the lower end of the speed range is only really good for about 1/3 HP at reasonable belt tensions. At middle speeds you may be able to do better.

The 1" belt is capable of 1 HP, but that takes about 1000 ft/min belt speed, IIRC, which the pulley system does not allow at all speeds.

A rubber and canvas belt will stand more tension than a leather one, and will allow maybe 50% more power (actually belt tension).

Ther are VFDs which take in 120V single phase and output 240V 3 phase, as well as ones that do the same with 240V single phase input.

Click to expand...

Good morning Bill
Yes,this is something I had an idea to do. Because my lathe is mounted on a sturdy wooden bench, that I have wrigged with adjustable screw feet for levelling purposes.
My idea is that it would make my lathe sort of mounted on a float pad and in this manner less obedient base than wood.
Problem is for now I'm anchored in house, at my age, no fooling around for a steel plate with a virus watching me.
Thanks and have a nice day.
Pierre

Good morning JST.
This is exactly what I have purchased this past December.
A 1" 4 ply polyester/black rubber like belting material 47.5" long of which one belt was assembled with a shark/pin connection and a second one to be glued, with the provided special glue. It was a very good Can $ deal to replace my broken, many times repaired leather belt.
I figured if the glued one failed I could revert to the pinned one,because getting the head stock off, is not always that convenient, plus in my case the temperature as to be warm enough for the glue to react, lets call it a summer job, for now the pinned one is installed and provides impressive traction when compared to my old leather strap.
As for the VFD, this 3 phase motor I can get for $100.00 old/new in the original box with for me very strange voltage, that is, 208- 220/440 volts.
I would like to be reassured before buying it, if a VFD plugged either on 120 or 240 volts 60hz. could provide the proper voltage to make that motor run.
I can't understand what I will do with a motor that can't run, on straight single phase residential voltage, if ever the VFD cant provide those very specific tri phase voltages.
Thanks
Pierre

Good morning 9100.
I dont happen to know the Mobil DT 24 kind of oil, it seems to have done a very good wear protection on your lathe, is there any other brands or name to get it ?.
Another thing I have never thought of checking, is the play on the spindle.It will get done.
The oil recommended in the" How to Run a Lathe Manual " has some strange call out numbers.
I may try to have them corresponding to SAE standards.
Thanks for your help.
Pierre

a 3/4 hp motor on a VFD is ideal for this lathe. You can find an inexpensive 120 volt VFD to run it, best if it is sensorless
vector capable, so you can get good torque at low speed. Motor is wired right to the VFD and use the logic controls on the
VFD to operate the lathe. Best if you remote the speed control and a fwd/off/rev switch to a small enclosure near the headstock.

If you put an automotive serpentine belt on the machine it will transmit power better than a leather belt.

I typically run spindles like this with synthetic automotive engine oil, Mobil One 0W20 grade.

Good evening M.Jim
That is good news a 3/4 hp and a VFD is all right for my lathe, not too big that is.
Funny,a guy ( he's quite younger then me ) with a machine shop not very far from here,recommended me this very same oil Mobil One 0W20 synthetic , saying he's using it wherever lubrication is needed on his lathe (Craftmans). For lack of better informations, the word synthetic and the strange oil grade 0W20 and his age got me cooled down about trusting that modern oil on my old lathe.
There must be some advantages I suppose.It wont gum up I hope?
Last but not least, will this 3 phase motor 208-220/440 volts I want to buy, run on a VFD with a supplied voltage of either 120 or 240....I checked with my voltmeter before getting back in house tonight, it was reading 119.3 and 240.6 .The residential voltage supplied here in my area is very, very stable, and this is what I will use to supply that VFD.
Thanks for your help.
Pierre

petrofun said:

Hello
Please forgive me if I'm not on the good forum.
I am trying to find out if a 3/4 hp 1725 rpm triphase 208-220/440 volts motor is too much for my fine little South Bend.
I'm not into production work in any sort, I use it mainly for modeling jobs, hobby parts.
It is just that, pleasure of a retired old man.
This motor is available (old/new stock) at a very decent price.
I have had this fantasy, to try and run a VFD, again this is no power trip.
I could use 120 or 240 Volts AC 60hz. as input voltage,(canadian household voltage) but I am not sure this would provide a suitable output voltage to run that kind of voltage on this motor.
Your thoughts and comments, will help me quite a lot
Thank you and have a nice day.
Pierre

Click to expand...

VFD and single-speed are not the same situation.

3/4 HP, three-phase, with "instant reversing" three-button Allen-Bradley control was factory-OEM, around 1959-60, when our school bought the so-called "toolroom" SB ten with the fancy flaking.

We replaced the leather belts twice a year, but only because teaching students how easy it was to taper and glue a leather belt was part of the training course.

Yes, 3/ HP can "chirp" the belts on instant-reverse.

No, it isn't over-powered nor an eater of belts otherwise.

It IS just about all the 9 and 10 SB's can USE, though.

Even so, if I were going to "VFD" one, I'd double that to 1.5 HP or 2 HP.

That isn't for more chip-ripping. The REST of such a light lathe can't take that.

It simply insures better reserves are left to stay smooth down at the lower end of the RPM band.

OT, but DC is the reverse. Low RPM is "naturally" great.

We use larger than usual DC motors for variable speed machine-tool applications because the TOP end, running in "Field Weakened" mode is indeed "weakened". Short as heck on Torque, low/no reserves, and harder to load-regulate without a big ration of reserve Torque/HP going-in.

No free lunch.

There remain significant advantages of their own to use of cheap and cheerful "mechanical" multiple pulley-diameter ratio choices, neither a VFD nor DC Drive.

Your case, you need it for converting off single-phase AND you will be KEEPING all of the OEM mechanically belted ratios TOO?

That works. Works very well. Your ratios let you not NEED the reserve from the motor alone.

Annnd.. Most of what a SB nine is actually ASKED to do needs but 1/3 HP, maybe 1/2 HP anyway.

"Go for it!"

Here are a bunch of links for DTE 24.


mobil dte 24 - Google Search


A wood bench is a poor mount for a lathe. Wood does not damp vibration well and it changes with humidity so you never know what stress the bed is under. The people who put cast bases under Monarchs, Mori-Sekis, Lodge and Shipleys, etc. didn't do it for looks.

Bill

Any bench is better than no bench. Wood by itself does tend to soak up oil, and there's typically
a fair bit of oil slung about under a lathe like this. Use a good solid finish to avoid that.

The spindle oil connundrum is wide and deep. My particular story goes like this:

I've owned three south bend lathes over the years. One of them was purchased so long ago,
south bend lathe was still in business. So I was able to purchase a number of factory items
including a correct SB can of correct spindle oil for that lathe (a 9" model A with the war production
board tag on it) and proceeded to set up the bearing clearances to factory spec (having previously
dismantled and inspected the journals and bearign bores - they were remarkably good) and filled
the oil cups with the SB oil.

Whereupon I found that if the lathe were run on the highest spindle speed for any time, the bearings
would heat, and the spindle would bog down. On advice from an old fart machinist from work (thanks
Rick) I drained the SB oil and re-fillled with the mobli one synthetic. All the problems went away.

I repeated this sequence of events when I traded up to a 10L machine (of similar vintage) with the
final end result being the same.

When I traded that machine for a more modern 10L, I cut to the chase and went directly to the synthetic
engine oil.

Devils advocate:

1) engine oils have detergents in them. They tend to hold particulates in suspection. All SB lathes of this
vintage are total loss lube systems. The oil goes in the oil cups and then comes out on the bench eventually.
I tend to drain and flush the oil reservoirs about once a year.

2) engine oils may have chemical components that attack bronze. I have not seen this in 30 years of running
the newer 10L machine, the bearing clearances do not change.

3) the original oil in your machine was probably not detergent type. While you are working on this, no matter what
oil you install, you should drain the reservoirs and flush them with clean oil until they drain clean.

4) read up on how to check the bearing clearances, do so, and adjust if needed.

thermite said:

VFD and single-speed are not the same situation.

3/4 HP, three-phase, with "instant reversing" three-button Allen-Bradley control was factory-OEM, around 1959-60, when our school bought the so-called "toolroom" SB ten with the fancy flaking.

We replaced the leather belts twice a year, but only because teaching students how easy it was to taper and glue a leather belt was part of the training course.

Yes, 3/ HP can "chirp" the belts on instant-reverse.

No, it isn't over-powered nor an eater of belts otherwise.

It IS just about all the 9 and 10 SB's can USE, though.

Even so, if I were going to "VFD" one, I'd double that to 1.5 HP or 2 HP.

That isn't for more chip-ripping. The REST of such a light lathe can't take that.

It simply insures better reserves are left to stay smooth down at the lower end of the RPM band.

OT, but DC is the reverse. Low RPM is "naturally" great.

We use larger than usual DC motors for variable speed machine-tool applications because the TOP end, running in "Field Weakened" mode is indeed "weakened". Short as heck on Torque, low/no reserves, and harder to load-regulate without a big ration of reserve Torque/HP going-in.

No free lunch.

There remain significant advantages of their own to use of cheap and cheerful "mechanical" multiple pulley-diameter ratio choices, neither a VFD nor DC Drive.

Your case, you need it for converting off single-phase AND you will be KEEPING all of the OEM mechanically belted ratios TOO?

That works. Works very well. Your ratios let you not NEED the reserve from the motor alone.

Annnd.. Most of what a SB nine is actually ASKED to do needs but 1/3 HP, maybe 1/2 HP anyway.

"Go for it!"

Click to expand...

Good morning thermite.
Yes I will definitely keep all the flat belt pulleys.
My plan is to install the original double vee pulley from the motor, on the 3/4 hp motor which will run with the VFD.
For now, my knowledge in machining does not include having to use instant reversing, maybe in the future but my preferences would be to first try and respect and learn about this very innovative for me, VFD installation.
I dont like seeing videos on YouTube showing people throwing around their tool, I wouldn't like to be their tool.
So for now your answers are well appreciated
Thanks Pierre

petrofun said:

Good morning thermite.
Yes I will definitely keep all the flat belt pulleys.
My plan is to install the original double vee pulley from the motor, on the 3/4 hp motor which will run with the VFD.
For now, my knowledge in machining does not include having to use instant reversing, maybe in the future but my preferences would be to first try and respect and learn about this very innovative for me, VFD installation.
I dont like seeing videos on YouTube showing people throwing around their tool, I wouldn't like to be their tool.
So for now your answers are well appreciated
Thanks Pierre

Click to expand...

Y'know... so long as you ARE keeping the full set of belts? AND NOT in need of, nor in love with (threaded spindle, yah?) on-the-fly reversing?

You could save the cost of a VFD and just start your journey with this particular lathe with a single-phase motor. They don't REALLY vibrate all to hell. Not a bit. And even so, the belts would damp it out. Small lathe, light cuts in any case.

Now. This because, after all, you can always change it LATER.

Or.. as many do... upgrade the entire lathe to a better one, and have spent less on the previous one.. to help get to the better one.. sooner.

as-in:

@las M6 6" X 18" --> recyling center. Didn't even save the drill chucks - I'm tripping over them.

1942 10EE 10" X 20" still here.

1944 10EE 10" X 20" still here.

1970'ish Cazeneuve HBX-360-BC 14" X 30"... still in the "foreplay" stage.

French goods can be serious interesting, but hard to understand for outsiders? My Renault Laguna surely was. But worth it. Way faster than expected, and on less fuel. Typical French black magic of making a car larger and more pleasing on the inside whilst smaller and homelier on the OUTSIDE?

.. and finally taking a pause if only for lack of SPACE!

You'd have to know "Old Iron disease"?

thermite said:

Y'know... so long as you ARE keeping the full set of belts? AND NOT in need of, nor in love with (threaded spindle, yah?) on-the-fly reversing?

You could save the cost of a VFD and just start your journey with this particular lathe with a single-phase motor. They don't REALLY vibrate all to hell. Not a bit. And even so, the belts would damp it out. Small lahte, light cuts in any case.

Now. This because, after all, you can always change it LATER.

Or.. as many do... upgrade the entire lathe to a better one, and have spent less on the previous one.. to help get to the better one.. sooner.

as-in:

@las M6 6" X 18" --> recyling center. Didn't even save the drill chucks - I'm tripping over them.

1942 10EE 10" X 20" still here.

1944 10EE 10" X 20" still here.

1970'ish Cazeneuve HBX-360-BC 14" X 30"... still in the "foreplay" stage.

French goods can be serious interesting, but hard to understand for outsiders? My Renault Laguna surely was. But worth it. Way faster than epected , and on less fuel. Typical French black magic of making a car larger and more pleasing on the inside whilst smaller and homelier on the OUTSIDE?

.. and finally taking a pause if only for lack of SPACE!

You'd have to know "Old Iron disease"?

Click to expand...

You know what, I have to watch myself a lot when its time for toy....ask my other half, she's a very effective alarm "siren"

petrofun said:

You know what, I have to watch myself a lot when its time for toy....ask my other half, she's a very effective alarm "siren"

Click to expand...

LOL! Have to be careful about yer better-half and sirens.

First year, mine would not venture past the doorway to the shop. Stood in the doorway, gobsmacked at all the old and greasy monsters hulking in silence and awaiting their baths.

Lightheartedly I said: "No fear. It keeps me out of pubs and brothels!"

Second year? I shudda had a new story. Said the same thing ....but she was no longer awe-struck.

"You never had a big problem with pubs. When did you start going to brothels?"

Women and score-keeping memory.

God surely made 'em in her own image, didn't she?

9100 said:

Here are a bunch of links for DTE 24.


mobil dte 24 - Google Search


A wood bench is a poor mount for a lathe. Wood does not damp vibration well and it changes with humidity so you never know what stress the bed is under. The people who put cast bases under Monarchs, Mori-Sekis, Lodge and Shipleys, etc. didn't do it for looks.

Bill

Click to expand...

Hello Bill
I've been trough a learning curve today about oils.
First I must be on the wrong side of the border, because Mobil DTE 24 is available here in Quebec, and due to the fact that it is an industrial grade hydraulic oil, it is only sold in US 5 gals pails at a mere $ 256.99 CDN.$ plus shipping and taxes, but the specs. tell of its qualities, well I cannot afford that.

As for the Mobil 1 OW20 synthetic engine oil I was suggested, it is only available in 6 U.S quarts pack for $109.00 CDN...........
in 6 quarts pack really?
A friend I was telling about my oil prices find this afternoon, said his brother was working in a machine shop a little while ago,
told him they where using automatic transmission for lubrication on all the lathes they had in that shop.
The prices I have found stunned me.
I could not find in my HOW TO RUN A LATHE South Bend manual, how to drain my bearing oil reservoirs.
I think I'm getting old ????
Pierre

Yeah! I will heed your counsel. she told me the other she was going to come and put some order in my shop.
That virus thing,,,,man thats nothing, I had a hard time going to sleep that night and I wasn't thinking about brothels either LOL.
I can see you've been converted, now you know God is a she...own image Yeah!
Boy you made me laugh, thanks
Pierre

petrofun said:

only sold in US 5 gals pails at a mere $ 256.99 CDN.$ plus shipping and taxes, but the specs. tell of its qualities, well I cannot afford that.

Click to expand...

I get some of my DTE lubes (several needed, each 10EE) from an aircraft supply who DO have smaller containers. OEM packaged that way, too - not decanted into no-name stock plastic bottles and jugs. Example:

Mobil DTE Light Turbine Oil, 1 Gallon, from Mobil, oil-dte-light - Chief Aircraft Inc.

As there is a use in the Aviation industry, Canada will surely have similar suppliers.

Many speciality lubes are also available from those who DO decant into smaller unbranded containers to support Hardinge and other fussier-than-SB lathes. Find those on ebay if you must.

I think I'm getting old ????
Pierre

Click to expand...

No fear. Getting old is a privilege, denied to many. Beats the alternative anyway.

That said? Cue "dry humour".


If you are ACTUALLY peeing AIR?

You are also dehydrated!

Or maybe just too frugal to invest in an air-compressor?

Don't put ATF in the spindle bearings for that machine, I advise against it. All other lube
spots, ATF works fine.

In the US the mobil one is available at any car parts store in one quart containers. Not sure why
the 6 qt requirment there....

jim rozen said:

Don't put ATF in the spindle bearings for that machine, I advise against it. All other lube
spots, ATF works fine.

Click to expand...

The guy I got my Sheldon R15 from was a strange duck. The lathe came with a jug of spindle oil in a compartment in the tail support, but he had it jammed up against a wall so he couldn't open the door. Instead, he put ATF in the headstock and let it sit for over a decade. The lathe was one of the last Sheldon made and was intended to have a variable speed drive, but they never got it finished. There was a motor mount in the headstock pedestal but he never managed to install a motor so it sat in the crate until I bought it. The ATF must have absorbed moisture at the contact points on the balls and rusted the races. It doesn't show in work but it whines. Likewise, automotive engine oils are made to absorb moisture. I don't use them in machinery.

If I mailed you a pint or two, would there be a problem crossing the border? I also use DTE 24 in hydraulic systems as it was intended, so I buy it in 5 gallon pails. I could mail you a little and never miss it.

Bill