[s-cars] Re: a very rough Audi weekend

[Paul Gailus]

Another thing to consider when using stainless nuts and
bolts is that they are prone to galling. As a result, the
joint may end up being under-tensioned even when it's
torqued to spec. Dare I say it, but this is one case where
antis**ze could help (trying to avoid another type of
galling thread & ducking for cover  ;-)

Paul

----- Original Message -----
From: Trevor Frank <tfrank at symyx.com>
To: JOHN TILDEN <j.tilden at verizon.net>; <s-car-list at audifans.com>
Cc: <mswanson at sonitrol.net>
Sent: Tuesday, July 22, 2003 3:51 PM
Subject: RE: [s-cars] Re: a very rough Audi weekend


>
> I am going to nit pick
> "hey may not rust, but have significantly lower yield strengths than
> grade 8 bolts"
>
> From memory...
> Grade 2=85ksi,     austenitic S.S. 304,18-8,316, OSH S.S. hardware.
> Grade 5=120ksi,       KS812 s.s. A286 and certain 304 conditions,
> Nitronic 50/60.
> Grade 8=150ksi,       A286 certain conditions,
> SHCS/allen alloy=160ksi-200ksi, 17-4ph, ARP300,   depending on size and
> manufacturer
>
> Not exactly correct, there are plenty of high strength stainless steel
> bolt's and nut's.  You will not find them at Osh but they are around.
> Generically Osh carries Austenitic 18-8 304-316 ish stainless steel
> allen bolts or otherwise have a yield around that of alum, 40ksi with a
> tensile of around 80ksi.
>
> I always replace bolts with ones of similar construction and strength.
> I almost always try to find them elseware before going to the steeler.
>
>
>
> -----Original Message-----
> From: JOHN TILDEN [mailto:j.tilden at verizon.net]
> Sent: Tuesday, July 22, 2003 11:14 AM
> To: s-car-list at audifans.com
> Cc: mswanson at sonitrol.net
> Subject: [s-cars] Re: a very rough Audi weekend
>
>
> This is a multi-part message in MIME format.
> --
> [ Picked text/plain from multipart/alternative ]
> Stainless Bolts are not a good substitute for high grade bolts! They may
> not rust, but have significantly lower yield strengths than grade 8
> bolts. Also, you can't reliably torque the stainless bolt to the same
> values as the high grade bolts for the same reason! They will stretch
> before you get near the desired torque value and will yield,
> permanently, leaving you with a dangerous condition.
>
> Be very careful when substituting hardware in our high performance
> automobiles! I always use OEM (read Audi replacement) bolts in those
> critical areas, brakes, suspension, steering, etc.
>
> John
> 1995.5 S6 Wagon
>
> j.tilden at verizon.net
> --
>
>
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