Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

I was going to suggest the Perfect U cut 49% deep or less as well.

  As I looked at the drawing Jim posted, it occurred to me the 3 points of contact pulley is also very much the same as the V-belt pulley we all know often used on lawn tractors and small engines.

I thought: would it not be cool if we could get extruded rubber cord like we use to make up custom length O-ring belts for our tiny engines BUT made in V-belt cross section (vs round) say 2mm width for example! There is something about the V shape that as you pull tension on belt it really grabs as it is pulled deep into its matching pulley.
  We likely don't need the fabric molded into the bigger V-belts as the stretch of pure rubber is quite forgiving on belt length.
  I googled micro V-belt and got this multi groove shown in the photo. I suppose you could purchase a belt like this and cut all the V's with a Really sharp knife and get several single V belts from one multi micro groove....but I like the idea of rubber cord in a V shape that we can super glue to custom length better...just food for thought. There may be a micro single groove v-belt maker out there.

In the end, round cross section O-ring type belts are really handy, but a V-belt option might be nice for that one specific implement that draw a lot of power.

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