On 12/2/2013 9:36 AM, Mechanical Music Digest wrote:

Robbie remarked:

>[ Polycord(tm) is a rough green thermoplastic polyurethane (TPU)
>[ round belting cord made by Habasit AG.

A more popular industrial polyurethane belting producer is Eagle.
Their products are available from several suppliers.  They make cross
sections in flat, v-belt, and round shapes.

Habasit is well known for its high quality flat laminated belting used
in various conveyor applications.  Their round belting products seem
to be aimed at filling out their catalog to give industrial customers
a "one stop shop" supplier.  Either product will be very good, but
Eagle will probably be easier to find and available at reasonable
stocking lengths.  Check the web site of Fenner Drives for Eagle
products:  http://www.fennerdrives.com/ 

Also, read the welding instructions (under additional information on
belt description pages) which describes using their kits to determine
if you can do something similar on your own without their kit.  Their
hot knife is available as a separate tool if you can come up with your
own clamping rig.

A 3/8" diameter or v-belt type polyurethane belt can be quite stiff and
not easy to use with small pulleys.  By the time you put enough tension
on the belt to get decent engagement in a pulley you can overload
shaft bearings, so you understand the risk of over-tension.

With a ball or rolling element bearing of any type, if you double the
belt tension, the life of the bearing will be reduced by a factor of
10, so a bearing that might last 20 years will last 2 years.  (In
engineering terms we say that bearing life is inversely proportional
to tension or chain pull raised to the 3.3 power.)

Don Shenbarger