Hi Steve -
Making the gross assumption that you have access to the bevel gear and the
mast that will allow you to create a "joint", I would recommend looking
carefully at the Kurt/K7NV recommendations. I have had a number of large
arrays on a 2"od x 1/4"wall seamless steel mast driven by a "small" PPM. I
use a split 2" id piece of pipe with two (over the years)increasing diameter
bolts. I can't even remember what's up there now - either 5/8"d or 3/4"d.
"I wish I knew then what I know now". Kurt's approach definitely looks good
to me. My current - for about 10 years - array is a 7-60 MHz LP - 15
elements on a 45 foot boom and it has developed at least 10-15 degrees of
slop.
Possibly you could drill and ream for a tapered pin while it's in place.
As I recall, Kurt's premise is that the problem is mostly getting and
maintaining a tight fit, size and material can provide the needed strength.
Good luck with your project and let us know how you make out.
Gene / W2LU
----- Original Message -----
From: <K7LXC@aol.com>
To: <towertalk@contesting.com>
Sent: Monday, November 07, 2011 2:50 PM
Subject: [TowerTalk] Pinning mast?
> Howdy --
>
> I've got a sloppy fit between a mast clamp and a mast - both steel. It
> won't shim properly so I think my only option is to pin the mast. I've
> done it a bunch of times and mostly they hold butr sometimes they don't
> so I'm
> proposing to use 2 in one direction and another two 90 degrees from the
> first two with good-sized high strength bolts. Other than the challenge
> of
> doing it at altitude, is there anything else I should be considering? Or
> is
> there another way to do it?
>
> This is a prop pitch with big antennas on it.
>
> Cheers,
> Steve K7LXC
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