Wes wrote:

I had to repair a machine today that uses a static reel to counter balance a slide
assembly that has a rotary encoder on a spring reel to measure displacement.

Looked like 1/8" cable over a 1.5" pulley that the cable wrapped 90 degrees. Just looked
wrong and the cable lasted 3 months. The cable is very lightly loaded, is there a ratio
of wire size and diameter to use in making the right sized pulley?

Thanks,

Wes



There are minimum recommended diameters of the pulley for every size and
type of cable, aircraft cable being the most flexible and requiring the
smallest diameter pulley for a certain diameter cable. Also, the
alignment of the pulley is critical to reduce rubbing of the cable on
the side of the pulley. Worn shafts or bad bearings will decrease the
life of the cable.



http://www.dir.ca.gov/Title8/8497.html


John