[TowerTalk] New Sheaves for Crank-Up

[F.R. Ashley]

I looked at those a few months ago and I would not use them even if they 
do meet requirements.   I agree with N0TT, they would probably not last 
long in the WX.

73 Buddy WB4M
>> 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
>
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