The easiest way to plumb a tower is the way the ancients did with their
Drop a plumb bob down from the top section.
If you have a top section with a point. I use a ball, big enough to sit on
top of the point. and a mason's line with a plumb bob going through the
ball. If your tower just has a top plate, you may need a bigger ball.
The ball will self center and the line/plum bob will also be centered inside
Just measure the distant from the line to each leg.
or draw lines from leg to leg on the base. where the lines intersect will be
Warning: Do not do this during high winds. ;-) and you don't have to buy an
expensive bob but Casa Depot has them cheap and you can always use it to
check your tower during yearly maintenance check.
----- Original Message -----
From: "Ray Benny" <firstname.lastname@example.org>
Sent: Saturday, June 29, 2002 12:29 AM
Subject: [Towertalk] Plumbing a tower??
> I'm new to the list, I hope someone can help with my problem.
> I have a 4 section, 71 ft motorized tower. It has 6 - 8 inch skids at
> the top and bottom of each section (not rollers) for the sections to
> slide as the tower is raised or lowered. I grease the sections once in a
> while with a non hardening grease. Its been up for 20 years.
> I have had a bit of a problem over the past year or so, I think it is
> caused by the tower not being perfectly straight. As I lower the tower,
> the sections bind causing the tower to descent in jerks. This jerking
> resonates and causes the tower to start shaking violently. I, of course,
> stop the motor and let the tower settle down. When I start the descent
> again, it starts this jerking / shaking again. Only until the tower is
> about half way down does the jerking stop. The same thing happens while
> the tower is being raised, but not near as bad.
> I do notice that there is some scaring on some of the tower skids, as
> well as the tower legs where the skids slide. I come to conclude that my
> tower is not truly straight. It is not visibly leaning, so it can't be
> off much.
> This tower has four bolts per leg and can easily and safely adjusted in
> the lowered position. I want to be able to measure, or relate the
> direction the tower is off. I also think that the torque of raising
> cable on pulleys can cause the sections to turn or twist somewhat, I may
> have to compensate for this as well.
> Any comments or ideas as to how to accurately straighten a tower? Anyone
> else have this problem?
> Ray, N6VR
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