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South Bend 9A - minimum belt length?

J-Gilly

Plastic
Joined
Sep 17, 2020
Hi everyone,
While I’m thrilled that I almost have my lathe set up, I need to order a new leather belt. 1947 South Bend 9A. With limited depth of my table ( a sturdy metal desk), and the fact that the back of the table is against a wall, the belt that came with my lathe is too long, at 57”. Due to limited space, I cannot pull the table away from the wall (I have a library ladder for overhead storage that slides left and right in front of the table / lathe. Using a rope around the pulleys, I think I need a 43” belt. I also need to cut down the threaded shaft for the belt tension adjuster, about 7”. The motor / countershaft assembly sits near the back of the lathe, with a couple inches of clearance, and nothing hits. Assuming I’ll make a cover / chip deflector for the motor, and that once bolted to the table, I can properly adjust the belt tension, is there any reason I should not have the motor / countershaft assembly so close to the lathe? As long as it works, would a short belt cause any problem (vibrations, harmonics, etc.)

Thank you for any help!

- Jon
 
Do not order a leather belt for your lathe. Go to the South Bend Lathe area of this web site and read the threads about using a truck serpentine belt. They work far better than leather belts, transmit much more power, don't stretch, and don't need to be as tight. You can ask a local garage to save you a used one and get it for free.
 
Do not order a leather belt for your lathe. Go to the South Bend Lathe area of this web site and read the threads about using a truck serpentine belt. They work far better than leather belts, transmit much more power, don't stretch, and don't need to be as tight. You can ask a local garage to save you a used one and get it for free.

Or you can shorten the belt you have. Leather can be spliced by skiving and gluing with Barge Cement. Or you can use Clipper brand metal belt lacing installed with a special clamping tool by a "power transmission" shop if there is one near you. The Clipper lace has a removeable plastic hinge pin that allows the belt to be threaded around the lathe spindle and then pinned, so you do not have to take the spindle apart. I have three leather belts with Clipper laces on one of my lathes. The belts have been running with no problems for over thirty years.

Or you can learn the old school craft of lacing a leather belt with strong thread (Kevlar, for instance) and a needle. I think I saw a page on hand lacing technique in an old copy of the South Bend How to Run a Lathe book. But here is an online instruction page for hand lacing using rawhide boot laces. I think Kevlar would work as well, with much smaller holes for the lace. Lacing Leather Belts - VintageMachinery.org Knowledge Base (Wiki)

Larry
 
Try Al Bino Industrial Belting for your lathe. I'm happy with the one on my South Bend.
 
A "gear belt" or "timing belt" works well too, just turn it inside out so flat side is to pulley. They are available in small increments of length and you probably want a 1" wide one. You do have to remove the spindle to get one on unless you cut and splice it. But worth the work to get rid of leather. The traction of a clean dry "rubber" belt is great.
 
Do not order a leather belt for your lathe. Go to the South Bend Lathe area of this web site and read the threads about using a truck serpentine belt. They work far better than leather belts, transmit much more power, don't stretch, and don't need to be as tight. You can ask a local garage to save you a used one and get it for free.

I have told many people about this trick; here is the link: Don't delay... do the Serpentine Belt Fix today!

However, it should only be used by someone who has had some experience running a lathe. The leather belt slips more easily if the compound crashes into the chuck, preventing further damage.
 
I guess no one has told you how short of a belt you can set it up for. I will tell you that the longer the belt is, the less you need to worry about how close the pulleys are lined up.
 








 
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