Date: Sat, 08 May 2010 14:07:22 -0700
From: Kevin Normoyle <knormoyle@surfnetusa.com>
Subject: [TowerTalk] Taco DMX install instructions (same as Delhi)
I was curious and found this.
Taco sells the same tower that Wade did as Delhi
The install instructions for Taco DMX are here
http://www.tvantenna.com/products/tvreception/mounting/towers/taco/dmx/DMXinstructions.pdf
They show bolts facing in, with a single washer at the nut, (not split
lock washer, a star lock washer with internal teeth.
They say "All bolts and nuts are specially heat treated"
## On Delhi towers... the bolt heads are in the outside.. and
nuts are on the inside. Same deal with Tryon. On my old LORD
tower.. 32" wide x 20' straight sections, they used 10 x 3/8" bolts
to splice each leg, 3 in the flat corner, and 4 on each side. They did
not stagger the hole pattern, so the nuts have to go on the outside.
## Trylon staggers the hole pattern... so nuts can go on the inside.
2 on one side of V legs is a little higher than the other side. In the case
of a Delhi, it makes no difference if nuts are on inside, or outside. If u put
the nuts on the outside, you have mote chances of getting stuff like coax,
rope, etc, etc, hung up on the nuts and any excess threads.
and "These special heat treated bolts have solid shoulders in order to
prevent the tower sections from shifting. Tighten the nut securely, but
be careful not to strip the threads".
If the nuts and bolts are heat treated, they must be at least grade 5?
Doesn't say if galvanized.
## it doesn't really say anything. Why not jus quote either a SAE G5/8
spec.. or an ASTM spec.... then you can relate to it. If you can tighten
up till you strip the threads on a 1/2" bolt.. look out. Any SAE-G5 bolt
or A-325 bolt uses 94 ft lbs for a galvanized bolt... and 39 ft lbs on a
3/8" bolt.
## I use internal star washers on SS machine screws. We used em also at work
on 1/2" bolts [cap screws] for inside iron work. Zero vibration though. On
these traffic
lights and tall lighting tubes... they all use galvanized split ring
lockwashers....
OR what appears to be a form of galvanized nylock. The galvanized nylocks
used on US Tower corp pulley's don't budge. Trylon uses galvanized split
ring lockwashers on all it's lower 5/8" G-5 leg bolts. My trylon was
installed
back in 1998.. and they are all still tight..checked over the last 2 x days
with the
new 2' long torque wrench.
## Apparently, on the latest eia-222 REV G spec... it sez some where abt the
only bolt allowed on new tower installs has to be a A-325 bolt... and one that
uses
a special captivated nut.... that also tells you how much toque has been
applied.
[torque indicating flat washers] They called em... 'self locking nuts'.
They also say that if any of the bolts are removed for what ever reason, the
entire bolt,
nut assy, etc has to be tossed away.. and can't be re-used. If you look at
power co
transmission towers that were put up yrs ago, they all used either G-5 [G-8 in
some places]
or A-325 bolts and split ring lockwashers. You never see any of those things
falling apart.
## when I dismantled the 600+ bolts in my old 30" wide L+R tower.. that was a
gov
install surplus tower... the bolts used had no marking on the heads.. and 99%
were rusted.
I could shear the shanks/threads with just a 1/2" socket wrench... so they
were no more
than G-2 mild steel. I replaced 600 of em with galvanized G-5 bolts I
purchased from
L+R. [ all 3x/8"... used for leg splices and also angle bracing.] I
lubricated the galvanized
bolts.. and quickly found that you could not put 40 ft lbs of torque on em...
maybe 2/3 that.
What happens if excess torque applied, and galv bolts lubricated beforehand is
this. The nut
would spin free ! Take the nut off... and it looked like you drilled it out
with a 1/2" drill bit.
The mating bolt had no threads.. all smooth ! What had happened is the
threads had come off
the nut and wrapped around the threads of the bolt... and ALL in one continuous
piece.
## did you check the other bolts on your delhi ??? Were any of them loose
?? You
may have just missed tightening the pair that fell out. What baffles me
is... the delhi
uses a 4" overlap on the legs [4.5" on a trylon] with the legs of the
upper section
on the INSIDE of the lower section. For your tower to fall over.. with no
bolts... the
bottom of the upper section legs [4" portion] would have to pop right
out..which is
extremely difficult. One guy here in town 'forgot' to tighten the 2 x
bolts at the 40'
level of his 48' delhi.. [ one leg only].. and one bolt fell right out. Both
nuts gone..
and 2nd bolt almost ready to fall out. The top section and F-12 5ba yagi
leaned
towards the section minus the bolt... not away from it..as yours did. With NO
bolts
the upper leg should have slid down the top of the section below it...
resulting in
a bigger overlap of sections.
## Check your top section out. Several delhi's here in town had loose rivets
in the
top 4' . I punched em out, then drilled em out to 1/4"...and replaced with
1/2-20
G5/8 galvanized bolts. I had 72' of delhi up at my folks place between
1976-1979.
Consisted of normal sections 9-8-6, then #5 straights up to the 64' level..
then I turned the
#4 section, into a top section, with new thick AL plates, and custom machined
right angle
tabs in the corners. 2 x thrust bearing used...and Prop pitch sat down 10'
down inside the
tower. 12 x guy wires too.... 4 x per level...and 3 x levels of guys. The
top 16' of tower
still twisted ! [ 2 x big yagi's on mast] I gave up on delhi's after that,
imo, they are just
not strong enough. The original 64' delhi was designed for deep fringe TV
ants.. that's it.
later on, they came out with the #4 + #5 straight sections. BX tower's in
the USA are
very similar design.. and they now say, no booms longer than 10'... I can see
why.
## IF they are carefully guyed.. like with a 6 x guy, star of david, monster
cue-rack
setup, it will be ok.
Later... Jim VE7RF
1/2" diameter x 3/4" bolts on bottom sections. 3/8" x 5/8" for upper
sections
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