South Bend 16 / 60 belt pulley

brovoechoseirra · Nov 23, 2020

Hello Everyone,

I posted a few questions a while back regarding a 16 x 60 tool room lathe that I had purchased. Other work had got between me and getting the new motor installed, so it has just been sitting.

So last week, I had some time to work, and my buddy and I started to install the new motor last Friday.
We were prepared to have to do a few mods, as the new motor had different mounting holes.

However, We discovered the original pulley for the motor was not correct, or even close. It is a two grove pulley, and the belt groves are not spaced the same as the ones on the driven pulley.
Apparently when the original motor was removed, the original pulley was swapped. At some time the lathe was probably being used with this mis-matched pulley, but how successfully, we dont know.
The belt alignment would have been pretty bad, and belt life would be short the way it is now.
My buddy did some research, and it appears that there were many options on sizes. He thinks that for most of the work we will do, we need a chuck speed of about 650 on the top end.

Does any one know what size this pulley should be to achieve a speed in this range?
Or even better, if we can buy a pulley?
I was hoping that some one might be able to measure their drive, as well as driven pulley and let me know what size these are?
Also, does any one know if these lathes ran 4 belts, or less? Since the driven pulley has 4 grooves, I suppose they used them all?

Thank you for any help that anyone can offer.

BES

Patrick Lawlor · Nov 23, 2020

brovoechoseirra said:
Hello Everyone,

I posted a few questions a while back regarding a 16 x 60 tool room lathe that I had purchased. Other work had got between me and getting the new motor installed, so it has just been sitting.

So last week, I had some time to work, and my buddy and I started to install the new motor last Friday.
We were prepared to have to do a few mods, as the new motor had different mounting holes.

However, We discovered the original pulley for the motor was not correct, or even close. It is a two grove pulley, and the belt groves are not spaced the same as the ones on the driven pulley.
Apparently when the original motor was removed, the original pulley was swapped. At some time the lathe was probably being used with this mis-matched pulley, but how successfully, we dont know.
The belt alignment would have been pretty bad, and belt life would be short the way it is now.
My buddy did some research, and it appears that there were many options on sizes. He thinks that for most of the work we will do, we need a chuck speed of about 650 on the top end.

Does any one know what size this pulley should be to achieve a speed in this range?
Or even better, if we can buy a pulley?
I was hoping that some one might be able to measure their drive, as well as driven pulley and let me know what size these are?
Also, does any one know if these lathes ran 4 belts, or less? Since the driven pulley has 4 grooves, I suppose they used them all?

Thank you for any help that anyone can offer.

BES

I have a 16 in its original configuration on my bench right now. After work I'll get the measurements for you. And yes, from the factory it had 4 belts although I've seen many people run it on less with some of the pulley grooves left empty.

Pic of mine:

texasgeartrain · Nov 23, 2020

Finding a 3 or 4 groove pulley for a 1.5 or 2hp motor not so easy. But its not really needed either, 2 belts is fine for that hp.

Top spindle speed on a 16 is about a 1000 rpm. Pulley OD you want is 3.25. You can find them new on ebay, but you need motor shaft OD as well. Belt thickness 4L.

Check this link through post #26:
Getting Another South Bend 16x6 Operational

Patrick Lawlor · Nov 23, 2020

markz528 · Nov 23, 2020

As far as I know, they came in two different diameters. 3.25 and 2.5 inch diameters sounds about right. I have the smaller pulley on my 1969 built 16 and the outer most groove is damaged and not usable. I picked up a new larger one from Ted some years ago (he didn't have the smaller one) but never installed it. I just run 3 belts. Been looking for a small diameter replacement pulley for years, and have not found one. Might make one some day.

The smaller pulley gets me in the 950 rpm max at 60 hertz. The larger pulley would put you in the 1200 rpm range.

As far as are 4 belts required, they sure are for the smaller pulley. Don't know about the larger pulley. I run an 8" chuck, and I had to slow down the acceleration rate to keep the belts from slipping.

texasgeartrain · Nov 23, 2020

A real handy pulley/speed calculator:
Pulley Calculator. RPM, Belt Length, Speed, Animated Diagrams

The upper vee pulley on a 16" South Bend is 12" OD. Assuming you're running an 1800 rpm motor at 60hz, so set rpm to 1800. Set small pulley diameter. You will see upper pulley rpm also.

Top spindle speed will be 2x the upper, large 12" pulley speed, as small step pulley on spindle is doubled in speed from its counterpart. Though you could measure the two step pulleys for flat belt to confirm.

South Bend spindle speed chart:

brovoechoseirra · May 23, 2023

Sorry for the pause in returning to the forum. There have been a lot of distractions in my life since I got the lathe, and first posted.
I wanted to update you all on my Lathe project, and let you know that I have got it running, and have been using it for some simple projects that I have been needing a lathe to complete.
I was able to get a belt pulley made, and get the new motor mounted.
So far so good, and I am spending some time getting to know the lathe, and gathering up some tooling. I have a lot to learn, but have my books from High School Machine shop, and have been learning, or relearning.
The one thing that I have to get working is the taper attachment freed up as it appears to be stuck and will not move.
I have some brazed carbide tools that came with the lathe, and have some more on order, that should arrive soon.
Should I order some high speed tool blanks, so that I can grind some forming tools if and when I need them?
I also need to order a boring bar kit, as I have a project that will require this.

My flat drive belt is pretty stretched out, and slips some. I have looked for some stick belt dressing, by I cant seem to find any.
Dad had a stick, and we used this on our flat belts, at our farm history demos.
I suppose we used it all up. Does any one know of a source for sticks of belt dressing?
Anyway that is about all that I have going on currently.

Thanks for everyone's help, both past and current.

Brad

texasgeartrain · May 24, 2023

Not sure about belt dressing. But for $75-$100 Baltimore belting will make you a new belt and ship to you. Use the 3/16" thick, and give them exact length of your's. I'd double check you are roughly in the middle of adjustment with your current one. If so, give them exact length. It'll come ready to go. Just slip it on and push the pin through.

Baltimore Belting – 766 E 25th St, Baltimore, MD 21218 (410) 338-1230

You could absolutely use HSS blanks. HSS can be ground with white AO grinding wheels, or green silicon grinding wheel.

Brazed carbide needs green silicon wheels. And the brazed carbide will need to be dressed on occasion. White or other AO wheels will NOT grind carbide. Green silicon and diamond works for carbide. The cheap boring bars are also brazed carbide. If your budget is tight, and you can grind free hand, get a cheapo bench grinder, than get the above mentioned wheels. For a few extra dollars you can a decent grinder that will allow you to set angles a little more proper, like this:

Heavy-Duty Tool Grinder

<h1>H7762 Heavy-Duty Tool Grinder</h1> <h2>Grind your own tooling with this Heavy-Duty Tool Grinder.</h2> <p>The H7762 Heavy-Duty Tool Grinder is perfect for the shop of any metalworker.</p> <p>The motor is 1/2 HP, 110V, single-phase, reversible, and 3450 RPM.</p> <p>The H7762 features dual...

www.grizzly.com

On taper attachment, there are two oil holes in the hanger. They lube a shaft that needs to slide when setting an angle. I bet its stuck there. Anyway, start at post# 53 of this thread, it might help you:
https://www.practicalmachinist.com/...uth-bend-16x6-operational.375566/post-3554537

brovoechoseirra · May 30, 2023

Thank you. I am so hit and miss with this thing. Its a super nice old lathe, but with all that I have going on in my life, I just dont get to work on it like i would like.
I ordered some tool blanks and will see if I can grind them and make them cut.
More to follow.

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