[TowerTalk] Rohn 45 Bent Leg

[Roger (K8RI) on TT]

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 at contesting.com] On Behalf Of Dave
> Leisman
> Sent: Friday, October 21, 2016 12:05 PM
> To: towertalk at 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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