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[TowerTalk] Pointy Top / Mast Binding - Tips?

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Subject: [TowerTalk] Pointy Top / Mast Binding - Tips?
From: (Bill Coleman)
Date: Fri, 20 Jul 2001 13:53:33 -0400
On 7/20/01 9:31 AM, Stan or Patricia Griffiths at 

>> Well, I have the mast inserted into the AG3 in the horizontal position. I
>> was just doing a test fit, and I don't have 15' ceilings in my basement
>> to test it vertically.
>Actually, you can do this test horizontally, like you are doing, just fine.

I think the problem was that with 6+ feet sticking out one side, and 1+ 
feet out the other, the mast was just rubbing against the bottom of the 
top end, and the top of the bottom end, causing the binding. It's 
basically lopsided when positioned horizontally.

When I stood it up vertically, the mast showed no tendancy to bind at all.

>> It's not tight, it just seems to take a bit of effort to rotate.
>Is there any chance that the 2 inch alumnum mast is really a little larger 
>than 2 inches?  Or could it be slightly warped?

I rolled the mast on (my not quite so flat) floor, and there's no 
indication it is bent.

Looks like 2" to me.

>> I'll have to move it outside vertically, rig up the rotator and try it
>> out a few times.
>It ought to turn real easy without the rotator installed.  If it doesn't,
>things can only get worse with the rotator in there.

Again, I only had problems with it horizontal. Once vertical, it was OK.

>> One item I have to figure out is how to line up the rotator shelf so the
>> rotator axis is parallel to the axis of the top.  Suggestions there would
>> be helpful.
>Early Ham-m rotators were made for 2 1/16" OD masts and binding occurred 
>if you
>did not shim them 1/32" from both points where the mast contacts bell 
>I am not sure, but I don't think this was a problem with later Ham-Series
>rotators . . .

This is a later Ham-M Series 5. I don't see how the mast connection could 
take anything larger than this 2" mast.

When I tried rotating it, the far end of the mast did not appear to try 
to move in a circle, so I don't think I have an axis problem.

>> I was planning to leave the shelf loose, then put the rotator in place
>> and have the mast position everything properly, then tighten the shelf.
>That is the right idea.  Tighten rotator ubolts first, rotator to plate bolts
>second, and plate to tower leg ubolts last.

That's what I did, and it worked great! I then removed the mast and 
rotator, leaving the shelf in place for me to hoist up later.

>> For my own piece of mind, I may coat the insides with LPS 2.
>It can't hurt.

After running my tests (which involved a complete rotation 3 or 4 times), 
when I removed the mast, I noticed a small groove at several points on 
the Al mast. Not enough to compromise the strength of the tube, but I 
will try to buff them out with a sanding sponge, and see if I can't 
smooth off the rough edges that caused this within the pointy top.

A lubricant would slow this type of chafing as well.

>Hope you get this worked out.  I simply never needed any of the complex 
>cures I have read about here on Towertalk . . .

I think it would have all worked out if I just put it up. But reading 
TowerTalk has made me wary -- I like to test things on the ground to make 
sure it will all work instead of being 40+ feet off the ground trying to 
figure it out....

Bill Coleman, AA4LR, PP-ASEL        Mail:
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901

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