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[TowerTalk] drilling chromoly es similar pipe

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Subject: [TowerTalk] drilling chromoly es similar pipe
From: (Lee Buller)
Date: Mon, 30 Jun 1997 17:10:10 -0500

Agreed about the bolt...but...most people believe (wrongly) that everything
will stay the same.  When you have wind, rain, sleet, snow, and various
other forms of weather above the roof line or tree line, something is
stressed.  If you use a bolt through a hole in the mast...the bolt or the
mast WILL give.  I understand that the bolt is not meant to take ALL the
torque, but people rely on them way to much.  I have seen bolts break and
holes wallow out.  Just a hugh expense and an accident waiting to happen.
Never...NEVER....drill a hole in a mast.  It is not worth it.  The rotation
of the beam will severelt over tax the bolt and the mast over time.
Guranteed.  K7LXC came up with a neat idea I had never heard of..and that is
to wrap the mast that goes into the rotor with some rubber and tighten the
rotor down.  I could see that gripping better than metal on metal.  Never
used the technique...but plan to shortly.

Of course...this is IMHO.


At 04:59 PM 6/30/97 -0400, you wrote:
>The bolt thru the mast isnt meant to take all the torque.  It's only there
>for insurance.  In case the clamp slips, it's not going to rip out coaxs
>and things like that.  It should, however, assist the clamp in some small
>amount...just dont rely on it exclusively.
>73, Tyler K3MM
> on 06/30/97 12:21:10 PM
>cc: (bcc: Tyler G Stewart/BENN/CEC)
>Subject:  Re: [TowerTalk] drilling chromoly es similar pipe
>At 01:15 AM 6/30/97 -0500, you wrote:
>>i am doing some antenna repair and part of the repair requires drilling
>>heavy mast.  by heavy i mean 1/2" wall thickness chromoly steel.  after
>>burning up several bits and a few $$$ let me pass this tip:  use a
>>masonry bit ( carbide tip ), lowest speed on drill press, and lot of
>>oil.  the most expensive bit i have used only did about 1/8 inch deep
>>( cost about $12 ) and the least expensive was the carbide tip masonry
>>type.  it has taken me over 4 hours of drilling to make a 5/8 hole in
>>some of this stuff but i am betting it wont bend!
>>put em up high and hope they stay up!
>>73, de bud
>Opinion:  I don't like any holes in my mast.  Now, I have never use
>Chrome-Molley masts and I know they are hard, but I have used steel masts.
>I have drilled holes to connect masts together..etc..etc...and the holes
>wallow out over a period of time.  The beam then really moves in the wind
>and damages the rotor.  I have tried all sorts of schemes to stop this from
>happening...using shoulder bolts, heating the metal and pressing on the
>bolts, etc...etc.  It will wallow out.  The best solution is
>never..NEVER...drill a hole in a mast.
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