[TowerTalk] Tower bolts etc..de K0FF

[Steve Maki]

"K0FF" <K0FF@ARRL.NET> wrote:

>Stainless and Galv may not be strong enough for a life-critical application.
>Grade 8 bolts are extremely hard and strong. Although for some reason, it's
>been said that they are too brittle for tower work? Any comments on this?
>Normal hardware store  bolts are grade 2 (unmarked heads), and are way too
>weak for anything critical. Grade 5 ( three hash makes on bolt head) are a
>good all around bolt that's strong yet ductile . The grade 8 ( usually
>plated a color like blue, and has several hash marks) is extraordinarily
>hard. I like to use grade 8 on most things, except towers. You can drive on
>into a poorly aligned hole  with a sledgehammer and still get the nut on
>afterward.

The standard hardware supplied with commercial towers (Andrew, PiRod, Rohn,
Valmont, etc.) is galvanized A325, which is a medium hardness (similar to
Grade 5 I believe) bolt made to exacting standards.  A325 is characterized
by large heads and nuts - IOW, you need larger wrenches. For example, 1/2"
A325 hardware has a 7/8" head, and either 7/8" or 1-1/16" nut, instead of
3/4" heads and nuts for regular 1/2" hardware.

BTW, I've NEVER been galled by A325 stuff - come to think of it, galling
with galvanized hardware in general seems rare compared to stainless, IME.

73,
--
Steve Maki

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