I'm in the process of refurbishing an old EZ-Way crank-up and
looking to replace some lift cable sheaves which have excessive wear
in the ID of the groves. The current 3" OD metal sheaves are sized
for 3/16" cable. The sheaves are rather narrow, measuring 0.38" at
the rim and 0.45" at the hub where the ball bearing is pressed in.
The tower sheave brackets will only accept a maximum sheave width of
0.50", and that's tight.
While looking at McMaster-Carr's web site (
http://www.mcmaster.com/#wire-rope-sheaves/=o71onb ), I was
surprised to see Nylon sheaves for wire rope applications. For the
size I'm looking for, they have the same load rating as the metal
sheaves shown near the top of the web catalog page.
Does anyone have experience with using Nylon sheaves in the lift
systems for crank-up towers? Somehow, this seems wimpy to me, but
they do meet my max width requirements and have the same load
ratings as similar sized metal sheaves.
I have a old EZ-way tower (RBX-50) and NO WAY would I
use any kind of plastic/nylon pulley on that lift system!!!
Sure, the nylon might carry the load when new, but nylon
eventually will get brittle in sunlight/WX and fail under
the load.
Just my 2-cents worth. :D)
73,
Charlie, N0TT
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk