I have a HyGain 70 foot crank up. The pully wheels (really idler wheels
over which the hoisting cable travels) on HyGain towers like mine are made
of some kind of metal but with a brass (maybe impregnated brass?) insert
at the center which forms a kind of bearing which encircles the axel bolt
which holds the idler wheel in place.
This brass changes shape under load and the hole it forms enlarges over
time. Thus, the idler wheels may not turn correctly or, worse, the brass
may totally wear away from its contact with the bolt/axel and the wheels
then turn on the other metal (maybe alumn.?).
Further, if the idler wheels are not absolutely in line with the line of
the pulling cables, these wheels will wear against the tower housing,
eventually wearing off one side of the wheel, allowing the cable to drop
between the wheel and the housing, binding in a very bad way.
A word to the wise. Check these things. de K4VUD
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