Whoa! ROHN states that it may be necessary to enlarge the bolt holes
with taper pin punches (do not drill out) They are definitely not a
precision fit because of the galvanizing.
I had to open roughly half of the holes in my 45G.
They go on to state: Do not screw reticent bolts into the holes, but
enlarge them first. Do not drill out the holes, use a taper pin punch to
carefully enlarge the holes. The same taper pin punches recommended to
be used to align the tower sections during alignment should work fine.
Any grade 5 or better bolt will work including SS, although the ROHN
bolt kit is recommended because of the galvanizing. Enlarging the holes
with these punches leaves the galvanizing in tact.
On my 45G, I used the punches in the small bolt holes in "each" leg
before installing the bolts.
If you use SS be sure to coat the threads with Never Seize. SS with out
the Never Seize tends to weld itself together making it necessary to
twist the bolts off which may require a lot of effort, making
disassembly difficult.
When using compound on threads, tighten adequately BUT be careful not to
over tighten and compress the legs. That tubing, by itself can be easily
bent. The tower depends on the entire structure for maximum strength.
Welding usually weakens the thin tube, but the towers are "usually
loaded far below their maximum and continue to work out their intended
lifetimes.
73
Roger (K8RI)
On 10/21/2016 Friday 2:09 PM, Hardy Landskov wrote:
Dave,
Just a FYI, the bolts you are using are not for Rohn tower. The correct
bolts are made for Rohn by someone and supplied when you buy the tower
sections and the bolt package so that the threads that stick through are not
in the shear plane of the bolts. They are galvanized, not stainless steel.
They are very close tolerance also. Not your ACE hardware overpriced junk.
I had a professional tower erector here to tell me the good, the bad, and
the ugly and we got it right when I put up my 110 footer. He used to put up
1500 foot TV transmitting towers in Tampa. If you want his email I can send
it. He can help you.
Hardy N7RT/4
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Dave
Leisman
Sent: Friday, October 21, 2016 12:05 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Rohn 45 Bent Leg
I need some advice. I have a 70' Rohn 45 and had a guy with a tractor back
into and damage one of the legs. As well, the leg was hit hard enough to
bend the diagonal cross support. I could probably, with assistance of a
come along, bend the leg back into place and bend the diagonal support back
into place as well, but that would not resolve the huge indentation which
resulted from the contact with the tractor., e.g., the leg's strength would
still be compromised. There is no antenna on top of the tower; I was just
getting ready to place my TH-11. The tower is guyed at 30' and 50' at the
current time.
My thought is to rent a mobile crane with a boom long enough and significant
enough to lift the 6 sections above the damaged section, in total (still
bolted together) from the damaged section; then cut the damage away from the
damaged section, and then lower the 6 sections down to the now repaired
section, drill all the holes and bolt everything back together. Is this
possible? I am concerned about climbing the tower, because of the damage
done to the leg - because somehow I need to strap the 6 undamaged sections
to the boom of the crane.
Another question is whether the stainless steel bolts holding the 6 sections
together are sufficiently strong enough to hold the 6 sections together
while I work on the damaged section.
I really don't want to start over because that means another hole to dig,
expense of more concrete, placement of additional guy wire anchors (and more
concrete), and waiting until late spring.
Any advice would be appreciated.
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73
Roger (K8RI)
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