[TowerTalk] multi-sheave pulley

[David Gilbert]

I also have a PST-71D rotator and it weighs a lot more than 50 pounds 
... 88 pounds if I remember correctly.  I used an inexpensive hand crank 
winch (turned by a cordless drill) to get it up to the top of my tower.  
You can get a crappy, but usable, worm drive winch from Harbor Freight 
for less than $30.

When I raised my rotator I could see steel filings being shed from the 
toothed gear and glinting in the sunlight as they fell even though I had 
it heavily greased.  The worm gear on my winch appears to be hard steel, 
but the toothed gear most certainly is not. Still, for what you want to 
do it should be fine.

I suspect that will be cheaper than any decent four sheave pulley you 
can find, especially since any inexpensive four sheave pulley as small 
as one or two inch is going to have enough friction to negate a 
significant portion of it's mechanical advantage.  Don't ask me how I 
know that.

73,
Dave   AB7E


On 11/13/2019 10:26 AM, Dave Sublette wrote:
> Good afternoon,
>
> I have to change the position pot in my PST-71 rotator for my Rohn 55
> rotating tower,  I guess the 10 degree temp last  night finally got to it.
> It has been going bad for a few weeks.
>
> The rotator is five feet above ground, but it weighs over 50 pounds.  I
> used to handle it with a pulley mounted on a 3 inch angle bracket which I
> temporarily bolt to the side of the tower a few feet above the rotator.
>
> The trouble is, at age 77 I no longer have the arm strength that I once
> had.  So,  I would like to use a multi-sheave system to reduce the force
> necessary to lift it off and reinstall it.  I have a two pully system which
> would reduce it to half, but I think I had better go with a three or four
> section system.
>
> All this to ask what is a good three or four sheave fully?  It only need be
> a two inch diameter. Or, a one inch would work also.  If you have any
> knowledge which one and where to get it, it would be appreciated.  In the
> meantime, I will do my own searching.  But, I thought it would be good to
> have the input of someone who has actually used what they recommend.
>
> As always, I look forward to the excellent advice that comes from this
> group.
>
> 73,
>
> Dave, K4TO
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