[TowerTalk] ROHN TOWER BOLTS

[Jim Thomson]

Date: Wed, 07 May 2014 16:41:00 -0400
From: Tom Nicholson <Gunsrus1942 at Comcast.net>
To: Mike Ryan <mryan001 at tampabay.rr.com>, towertalk at contesting.com
Subject: Re: [TowerTalk] ROHN TOWER BOLTS

NO FLAMES HERE!

Here is what I have for choices:

Not the average Home Depot / Lowes "Stuff"


A286 Super Alloy?With approximately 26% nickel and 15% chrome, this 
iron-based super alloy brings you the strength of alloy steel with 
corrosion resistance similar to 18-8 stainless steel. It meets ASTM A453 
Grade 660 and is not magnetic. Screws have a minimum Rockwell hardness 
of C31 and minimum tensile strength of 140,000 psi.

17-4 PH Stainless Steel Alloy?Combines the high strength of alloy steel 
with the corrosion resistance of stainless steel. It meets ASTM F593 
Grade 630 and is magnetic. Screws have a minimum Rockwell hardness of 
C31 and minimum tensile strength of 140,000 psi.

Alloy 20 Stainless Steel?Also known as Carpenter 20 screws. With 
excellent resistance to sulfuric acid, these screws have a minimum 
tensile strength of 80,000 psi.

I also have a choice of 18-8 or 316 SS Nylon lock nuts.

Tom W1ALZ


##  18-8 is now history...and replaced by the 3XX  series of hardware.
The 3XX is  still 18-8.... its just a numbering change. 

##  Compare  G-5 bolts and mating nuts  with your proposed
SS  alloys you listed above.   (SAE-G5 is the same as astm  A-325 bolts.)

##  I had one helluva time when using  SS  bolts  with the mating SS nylocks a few 
years ago.   I had several cases where the SS  nylock nut  would seize up badly...
just before it was even finger tight.   Never had a problem when using plane jane
SS  nuts.    Dunno what it was with those SS nylocks.   I would recommend running
a  tap through the SS nylocks.....and running a die down the SS bolts.   All  you need
is one tint ding in the threads..and the damned things  will seize up......and that’s
with never seize already applied. 

##  On a similar note... a buddy of mine has a K0XG  rotating 55 G  tower.  His top 3
sections are the beefed up sections...with the extra diagonals in them.   They weigh
a bit more than regular 55G sections....and look like a continuous X.... plus the usual
horizontals.    He has 25 feet of this beefed up sections above the very top ring.

##  A few months ago, one of the bolts fell right out...and landed next to the tower base. 
Upon inspection, the nut from the 2nd bolt on the same leg has vanished !   This install 
is new as just a few years ago.   The vibration at times appears to shake the tower pretty
good  with the myriad of yagis installed on it.   Dunno why Rohn didn’t use nylocks everywhere.
UST uses  nylocks on everything.   Apparently the new style Rohn nuts  are one time use only,
and will not vibrate  loose.   Think about it for a minute......putting a  nut on a bolt that is through a 
tubular leg is asking for trouble imo.  The nuts is not bearing  down on a flat surface but a curved 
surface.   You can only crank so  much torque on those bolts too. 

## Hopefully the new style nuts  fair better.   Nylocks or the use of loctite blue..thread locker
would also work.   Loctite also makes  loctite  purple..which is slightly weaker than the blue stuff. 
Dont use locite red..or you will never get the nuts off.   Freaks me out when you see bolts and nuts
falling off at the 180 foot level of a 190 foot tower. 

##  whats really needed is mating  THICK washers..that have a curve on one side..to mate to the curvature 
of the tower leg...and flat on the other side..so the nut can bear down on a flat surface.   

Jim   VE7RF