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Re: [TowerTalk] Seized mast clamp bolts Hy-gain 10 meter yagi

To: "Mike Besemer \(WM4B\)" <mwbesemer@cox.net>
Subject: Re: [TowerTalk] Seized mast clamp bolts Hy-gain 10 meter yagi
From: "Steven H Sawyers (na0ia)" <steve@sawyers.org>
Date: Sun, 03 Jan 2010 19:50:22 -0600
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
  I also recommend an anti seize compound. Make sure the compound 
specifies that it is good for stainless hardware. Some of the 
compounds used for exhaust manifold bolts have a high nickel content 
which will not work well for stainless.

de na0ia

At 07:39 PM 1/3/2010, Mike Besemer \(WM4B\) wrote:
> >From http://www.estainlesssteel.com/gallingofstainless.html...
>
>
>"Thread galling seems to be the most prevalent with fasteners made of
>stainless steel, aluminum, titanium, and other alloys which self-generate an
>oxide surface film for corrosion protection. During fastener tightening, as
>pressure builds between the contacting and sliding thread surfaces,
>protective oxides are broken, possibly wiped off, and interface metal high
>points shear or lock together. This cumulative clogging-shearing-locking
>action causes increasing adhesion. In the extreme, galling leads to seizing
>- the actual freezing together of the threads. If tightening is continued,
>the fastener can be twisted off or its threads ripped out."
>
>I always use an anti-seize compound on stainless hardware.
>
>73,
>
>Mike
>WM4B
>
>
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com] On Behalf Of Dana Roode
>Sent: Sunday, January 03, 2010 8:32 PM
>To: towertalk@contesting.com
>Cc: Dana Roode
>Subject: [TowerTalk] Seized mast clamp bolts Hy-gain 10 meter yagi
>
>Howdy - I assembled a new LJ-105CA 5 element Hy-Gain yagi for 10
>meters this past week.  I put it up temporarily on a mast to work on
>it.  For some reason 3 of the 4 5" stainless steel bolts on the mast
>clamp seized to the nuts after I raised the yagi on the mast a few
>feet and tried to re-tighten them.
>
>Anyone know why this happens?  The bolts are new, although they have
>been in the box with the rest of the yagi parts for several years.
>The beam is also unbalanced at the mount point and that may have
>torqued the bolts as I was moving the beam around (BTW, is it worth
>trying to balance this yagi before it goes up?).
>
>When I replace the mast bolts, should I go with stainless steel as
>Hy-gain does or some other material?
>
>I also have the same antenna for 15 meters that is on top of a 45'
>military tower.  I noticed those bolts are seized as well when I
>checked to see if they were still tight.
>
>   Dana
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