Please check the head markings on your galvanized Grade 8 bolts.
If they're actually Grade 8, they'll have 8 radial lines marked on
the head. The reason I ask is that I've never seen a galvanized high
strength alloy steel bolt. Grade 8 bolts are typically plated and
have a gold color.
The ASTM A490 specification for high strength bolts does not allow
galvanizing because of the high risk of reducing the strength of the
heat treated steel alloy during the hot dip galvanizing process. SAE Grade 8
bolts use the same high strength alloy as Grade 8 but they're
less expensive (and more common in consumer stores) because the SAE
specification doesn't require testing.
I understand that some overseas manufacturers do offer mechanically
galvanized (N O T hot-dip galvanized) high strength steel alloy bolts.
I suspect they're much more expensive than plated SAE Grade 8 bolts and
they're probably not readily available in the USA.
The alloy steels used in high strength bolts are brittle and achieve their
fastening strength only when properly tensioned by
professionally trained installers with special tools and methods. Its
very unlikely that high strength bolts actually achieve any benefit in
amateur installations, and can actually be very hazardous if not
My advice: Don't use high strength bolts unless you're a trained and
experienced professional. In critical applications, use ASTM A325
bolts which can be safely installed by non-professionals. In less
critical applications use SAE Grade 5. If you must use high strength
bolts, obtain the training and equipment to use them safely.
---- Original message ----
>Date: Thu, 18 Oct 2007 13:13:18 -0700 (PDT)
>From: Jeff Walker <firstname.lastname@example.org>
>Subject: [TowerTalk] Galvanized grade 8 bolts
>Galvanized grade 8 bolts are available in bulk at a
>VERY reasonable price from...
>Gulf Coast Fasteners, Inc.
>1626 Town Hurst
>Houston, Texas 77043
>Do You Yahoo!?
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