View Full Version : Converting a South Bend 9 to "regular" belts?

08-26-2005, 12:09 PM
I keep missing out on the eBay auctions for replacement belts for a South Bend 9. Anybody know of conversions to a rubber belt of some type? Or is this another Really Bad Idea?



08-26-2005, 12:17 PM
There was an article in HSM or MW about just such a thing a while back,i got acouple of bits of iron and a spare SB flat belt pulley
and was all set to make a conversion, but never did.
Dont really mind the flat belt,
I had my WW2 SB9 peeling off something like .4
inches a pass (.2 depthof cut)in 304 stainless a few weeks ago.
Flat belt hops off before you get your self in trouble.

08-26-2005, 12:41 PM
Actually, that was the first thing I thought of when I considered down sides of the conversion. I have run the carriage into the movable stop with the power feed, and having the belt slip off is a more gentle slap-in-the-face, as opposed to the shot-in-the-foot crash damage.

It's just that the leather is such a pain (and expense) to track down. I can live with learning to be more careful if I can keep the machine in belts. I haven't broken the only one I have yet, and that's partly why I also don't keep it very tight. I really don't know how much tension it will take before giving out.

08-26-2005, 12:44 PM
<font face="Verdana, Arial" size="2">Originally posted by thistle:
I had my WW2 SB9 peeling off something like .4 inches a pass (.2 depthof cut)in 304 stainless a few weeks ago.

Whoa! I just re-read your post. That's quite a cut! I was cutting 304 last week, and I don't think I could do that. Please tell me about the cutter and coolant setup you used.


08-26-2005, 02:15 PM
Lots of the folks still running SB flat-belt drives have been using car flat belts instead of the leather. Run it flat side to the pulleys and it works fine.

I'm going to be doing this myself when I get my SB set up - till then I'll just have to cope with my Myford...(boo, hoo)...8*)

08-26-2005, 04:11 PM
I re-belted my S.B. lathe with leather and alligator clips or lace.

What I dont see is why would you use a continuous belt. You would have to remove the spindle and drive pulley to replace it. The alligator clips were a snap. JRouche


Search: flat belt

08-26-2005, 06:29 PM
i dont know what or where they came from. but when we bought this place there was a bucket of beltingit is a rubber.i made up a new belt for my 9" and it works great.

i like the flat belts because you can hear what is going on in the shop. not like some of the gear grinding lathes i have run before.

Paul Alciatore
08-26-2005, 06:49 PM
I installed an automotive style, serpentine belt on my SB9 a few months after I bought it. It has been on for about two years now and I love it. Very little stretch so very little adjustment. It will likely outlast me.

Downside is you have to take the headstock and countershaft apart to install it. But even that proved to be a plus as I found that the oilers in the headstock were worn down to the nibbs and the the springa were scraping on the spindle. I replaced the oilers at the same time and all is well. I think the countershaft also benefited from the disassembly and cleaning.

Also, the tension is a bit harder to set up, at least at first. The belt wanted to jump off at first and I had to use more tension than I was acustomed to with the leather belt that came with the lathe. I think the belt has relaxed a bit in use and tension is no longer a problem.

Just measure your old belt and go to the nearest auto parts place. They can find a serpentine belt from the width and length. And it is a lot cheaper than some of the other alternatives. Even cheaper than leather.

As for which side to use, I have heard opinions both ways. I don't think it matters. But try it and make up your own mind.

And no Click, Click.

Paul A.

08-26-2005, 07:40 PM
When I needed a new belt for my SB9, I found Baltimore Belting Co. (www.baltimorebelting.com) at (800) 225-2358. I told them what I needed, they told me leather was expensive but offered a leather belt at $19 and suggested a "transmission belt" (rubber-impregnated cotton) for $8. I ordered the transmission belt; it arrived 2 days later, complete with clipper lacing, clearly marked as to direction and pulley-side. I've been running it for about 9 months now.

Nice folks, very prompt, and very reasonable. Why convert to V-belts?

08-26-2005, 09:05 PM
<font face="Verdana, Arial" size="2">Originally posted by Wirecutter:
Whoa! I just re-read your post. That's quite a cut! I was cutting 304 last week, and I don't think I could do that. Please tell me about the cutter and coolant setup you used.


1 3/4 inch bar cutting with Just HSS lots of rake ,speed -think i pushed it up to 235 rpm ,feedif i remeber 0.0095,
with black cutting oil,as this lathe does not have a coolant pump.
Probably better to flood cool the Stainless .

I wanted to push it up to .5 a pass but the
machine was not happy to do that,it is after all a well worn war production machine.Love to get a spanking new one .

The South Bend book "how to run(ruin)a lathe"has some pics of really heavy cuts .
my machine as i said pops the belt when i get to heavy with the load,
while it is expediant to take a heavy cut once in awhile,normally I try not to wear out the old girl to quickly.

08-26-2005, 09:40 PM
I submitted an article to HSM about converting to "poly-V" belts with 20 speeds.
It's supposed to be published in the near future. (at least that's what they told me at NAMES in April)

Your Old Dog
08-27-2005, 06:59 AM
I went to a belting company in Buffalo and bought a belt made of man made material that you put on yourself. It's ends are cut with a very serious bias on both axis. You then use this special glue they give you and clamp it up in a homemade jig to keep it all straight. a couple of C clamps for a day or two and its ready to use.

I've left weight on it and no stretch. It is more forgiving if I screw something up in my set up. It wasn't cheap, cost me just over $100. I don't plan on every having to take it off.