[Towertalk] Re: Help! Heavy Wind Batters Beam and Rotor

[WA2BPE]

This was posted by K8IA a few days ago re: various Loctite grades & uses.  I am
pasting it here as it may have been lost by some (saves looking in the archives)
and is pertinent.

73,  Tom - WA2BPE

**************************************************************
 Five different grades of
Loctite are used in my garage.

1) Loctite Threadlocker 222MS Purple - Recommended for small fasteners up to
1/4" (6mm) diameter and larger componenets that require occasional
readjustment. Allows disassmbly with hand tools.

2) Loctite Threadlocker 243 Blue (old #242) - Medium strength thread locking
adhesive for 1/4" thru 3/4" (6mm to 20mm) diameter fasteners. Parts can be
separated with hand tools.

3) Loctite Threadlocker 271 Red - This stuff is fairly permanent and requires
much effort to remove. It is used for permanently locking studs and press fit
assemblies, replacing set screws and snap rings etc in the
motorcycle/automotive world. In the past 25 yrs I have neve seen anything
come loose after an application of "Red".

4) Loctite Threadlocker 290 Green - Used on fasteners from #2 to 1/2" (2.2 to
12mm). Localized heating and hand tools are needed for disassembly.

5) Loctite Threadlocker 262 - Used on 3/8" to 1" fasteners that must
withstand unusually heavy vibration, shock, or extreme chemical/environmental
conditions. Localized heating and hand tools are needed for disassembly.

All the above come in small 6ml tubes, available nearly anywhere, and larger
containers for shop use.

I hope this info helps.

Bob K8IA
***********************************************************
K7LXC@aol.com wrote:

> In a message dated 4/22/02 9:54:43 PM Pacific Daylight Time,
> jsbmjb@theriver.com writes:
>
> > I have a Force 12 C-36XR beam (36' boom, 108 lbs, 13.8 sq ft, 120 in-lbs
> >  torque) mounted on a Tail Twister rotor with 5' of 2" chrome-molly mast
> >  in Santa Cruz County Arizona (75 mph winds).  I'm located on top of a
> >  hill and have days and days of 25 -35 mph winds.  So the antenna and
> >  rotor are pounded with 12 - 16 hours of wind a day for 100 or more days
> >  a year.
> >
> >  The first failure and I hope the last, was all the bolts holding the
> >  rotor to the rotor plate loosened and fell out.  The beam and rotor have
> >  been removed from the tower and are on the ground.
> >
> >  What changes do you recommend before I return them to the top of the
> >  tower?  I would rather spend my time operating than tower climbing and
> >  repairing my antenna and rotor.
> >
> Hi, John --
>
>     Well, the problem with the rotator base bolts isn't common but does
> happen as you've observed. Something M2 does is use aircraft-type bolts with
> drilled holes in the head so that they can be safety-wired. The T2X bolts are
> real common (the M2 ones are fine threaded) so you should be able to get them
> from an aircraft parts supplier. Check the yellow pages or do an internet
> search for sources. There are a couple of airplane owners on TT who can
> probably help you with this. Or you can drill them yourself.
>
>     You could probably use some LokTite on the threads - that'll discourage
> them from loosening. I think it's the blue version that will allow them to be
> removed at some point. There's another color that WON'T so be sure to ask the
> salesperson for the right one. Available at any auto parts store.
>
>     I'd also encourage you to do an inspection at least once a year - in your
> case maybe more. That way you'll catch something before it becomes a problem.
>
>     In the case of the F12 antenna, I'd put another row of rivets opposite
> the existing ones on the elements to really lock down the element joints.
> With just one row of rivets, the elements have been known to work loose in
> windy environs. Adding a third row so the rows are 120 degrees apart wouldn't
> hurt if you're a little ambitious.
>
>     Also adding a couple of bolts thru the boom-to-element clamps is highly
> recommended as well if they don't already have them. That's another place
> where the rivets have been known to work loose.
>
>     With that big antenna you get big stresses on the boom-to-mast clamp. In
> the last 2 months I've seen two that were just ripped apart - both were
> installations on ridge tops. You may want to add another plate (so the total
> one is thicker than stock). If the antenna isn't twisting around the mast
> now, then it probably won't in the future. But beefing up the mast bracket
> will eliminate that potential problem.
>
>     Other than that, you should be good to go.
>
> Cheers,
> Steve     K7LXC
> TOWER TECH -
> Professional tower services for industry and amateurs
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