W1km@aol.com wrote:
> I have an old antennamart prop pitch which has a 1 7/16" dia shaft --anybody
> have any ideas on how to couple this to a rohn mast--I'm afraid just sliding
> it over the shaft and pinning might not be the best way to go.
You are right - the hole in the mast gradually wears bigger, and the pin
wears out.
What we did was to grind the shaft down flat around the hole on each
side, from the top of the shaft almost to the bottom. We ground enough
shaft away to end up with approx 1" wide flat sides. It really didn't
take too long - maybe an hour - with a big hand-held grinder, to do a
nice job.
Once you have these two flat sides, the task of designing a no-slip
clamp becomes easy.
Our way was to use two pieces of angle (maybe 1.5" x 1.5" x .25" x 4")
which are drilled and bolted to the shaft.
A piece of channel is bolted to the angles, and the mast is u-bolted
to the channel. Of course, care must be taken to line up the shaft
with the mast. We had no trouble with it.
A picture is worth a thousand words, so I'm attaching a small jpg
to a direct e-mail to you Greg. It also shows our other modification
to the rotator. We cut out a chunk of the cannister side to allow
easy selsyn replacement.
--
Steve K8LX
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