Odd pulley size on Singer industrial machine, having a hard time finding the correct belt

[rk5n]

Hello all, I have a Singer 136-W110 post bed machine that I got last year. This would be my first industrial machine with a motor (I also have an Adler 67 I've been hand cranking) and I'm trying to attach a Consew CSM1000 servo motor. The pulley on the servo motor is a standard 3/8" wide for a 3L belt, but the pulley on the Singer 136 is narrower and a 3/8" wide belt only sits in the pulley by about 1/16". Is there a different type of belt to use, maybe a round one? Looking over these forums, I can't be the only one with this issue assuming the pulley is standard to the machine, a lot of other people are using older singers with new servo motors. I'm primarily sewing shoe uppers, two layers of 5oz leather at most. I'm worried the belt will slip on the pulley since it looks to not have a lot of contact and I want to sew as slow as possible so momentum won't help.

 

 

Edited December 1, 2017 by rk5n

[GPaudler]

It's not unusual to encounter odd-shaped pulleys on old machines. Give it a try,  there's a pretty good chance that there's enough contact on the larger pulley even without full engagement. In my experience when belts slip, it's usually on the smaller pulley.

[Wizcrafts]

The pulley was probably meant to be used with a round, 5/16" diameter leather belt

[mikesc]

Try using a "toothed belt", they fit a little deeper into the pulleys, and they go around the smaller diameter pulleys much better as the inside of the belt is not being compressed .

[Evo160K]

rk5n ,

My 99 yo Singer 45K53 has the same belt/pulley arrangement you describe, even has the consew CSM 1000.  It all works fine, no belt slippage, however the previous owner must have tightened the rubber v-belt, because it has a metal "staple" in it.  If you don't want to use a staple, there is an outstanding rubber adhesive called RP-30 by Adhesive Systems, Inc., www.instantca.com that works great.