Round Belting - Solid vs. Hollow, Polycord vs. McMaster

[Chris Fultz]

Originally Posted by Kims Robot

Slightly different topic, but has anyone compared V Belt to the Polycord? Has anyone USED V Belt on a robot before? We found tons of examples of teams that used polycord, and have even used it ourselves, but have been experimenting with V Belt in our initial prototypes. It seems to work well and slip out less, but one of our mechanical engineers was thinking that as its used it has more potential to come out of the pulley...

Any thoughts?

We have used synchronous belts - they work well, but you need to design around a standard size and alsignment is critical or they will walk aout of the pulleys. V belts would be more tolerant, as they are continually being 'forced' into the v-groove. However, v-belts 'seem' to stretch more, because as they wear they get seated deeper into the pulley.


Regarding poly-cord like belting - the recommendation we received is 8%, and that is working. The belts are stretched to install but are holding up well (so far).

Also, both McMaster Carr and Durabelt provide minimum pulley diameters for each belt size. For 1/4" cord, MMC recommends a minimum of 2", Durabelt recommends 1-1/2 - 2", depending on the load being carried.