[TowerTalk] MonstIR/Orion (mast clamp slipping) problem

[Magnus A]

I would definatly use Loctite 247. It is blue.

There are some green ones that probably would do it like 648 but they are 
supposed to be used in warm applications. The 247 is better in overall 
temperatures and opens using about 20-40Nm more then what you tightened it 
with.

73 de Magnus SM6WET


----- Original Message ----- 
From: "Mark ." <n1lo at hotmail.com>
To: <towertalk at contesting.com>
Sent: Tuesday, February 28, 2006 6:10 PM
Subject: Re: [TowerTalk] MonstIR/Orion (mast clamp slipping) problem


> Howdy Steve, et all;
>
> I'll throw out a couple of ideas that might be helpful.
>
> 1) Try some anaerobic joint locking compound (threadlock/'Locktite' type
> stuff) between the mast and the clamp. Try the blue/medium grade, which
> should be easily removed for maintenance using a heat gun. The 
> red/permanent
> grade will be stronger, but harder to remove (anyone have practical
> experience removing red grade?).
>
> 2) Install a square mast adapter. It's not like the Slippnot, though, but
> requires some custom machining. Fortunately, this can be done in the 
> comfort
> of a shop, before climbing.
>
> The adapter fits on the bottom of the mast to convert it to a square cross
> section. The upper portion would be a light slip fit around the OD of the
> mast for a length of 8-12 inches or so, and would be kerfed on 2 sides, 
> 180
> degrees apart (like a Yagi element joint). The lower portion would have a
> square cross section sized for a secure grip by the mast clamps on the
> rotator.
>  Multiple muffler clamps placed on the outside of the adapter create an
> adjustable friction fit, that could still slip and protect the rotator, if
> desired. Keep adding clamps to add more friction. This approach requires 
> no
> drilling for conversion on the tower!
> If you desire the pinning approach, the adapter and mast could be drilled
> for a number of bolts or pins to multiply the torque they can hold before
> shearing. The bolt/pin diameter and metal can be chosen to shear at a
> certain torque that is still higher than what an average windstorm might
> generate, but lower than that which would damage the rotator.
>
>
> For bolt loosening, I think you are referring to permanent (plastic)
> stretching of the mast clamp bolts. Assuming the mast clamp parts are 
> beefy
> enough, a higher grade and/or larger diameter mast clamp bolt might 
> prevent
> them from loosening by permanent stretching.
>
> Good luck,
>
> --...MARK_N1LO...--
>
>
> Steve asks:
>
> <<Howdy -
>     I've installed 2 MonstIRs and they both used the  Orion 2800 rotator
> with
> a pinned mast clamp/mast. In the last windstorm, they  both started 
> turning.
> I used an SAE graded bolt for pinning them both and they  both broke. I'm
> going to replace the mast pin with a bigger bolt but I'd like to  come up
> with an
> additional way to keep it from coming loose.
>     Tom, K5RC, has come out with the SlippNot for  Hy-Gain type rotators
> that's adds additional holding power to the rotator/mast  connection - 
> sort
> of a
> belt-and-suspenders approach. That's the direction I'd  like to head in.
> Does
> anyone have any additional suggestions? I'd appreciate  it.
>     BTW my experience with M2 Orion rotators is that  over the years, just
> about 100% of the mast clamps have eventually loosened up.  After much
> research
> and investigation, I attribute it to bolt stretch;  particularly since
> nothing
> you do to the nuts (LokTite, double-nutting, etc.)  seems to help.
>
> Cheers, Steve     K7LXC TOWER TECH - Professional tower services for
> amateurs
> Cell: 206-890-4188 >>
>
>
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