I think the comparison in question is to heat treated and hardened aircraft
bolts.
In a non-race, non-critical application, such as a daily driver
passenger car water pump, I'd guess that stainless steel bolts are just fine.
Stainless steel bolts are weak and brittle? This is counter to
everything I have ever heard in boat construction. Of course,
there, you are comparing a stainless steel bolt to an aluminum
one, or a steel bolt that will rust after about 5 minutes
exposure to salt air/water.
Exactly the point. I was comparing to Grade 5, Grade 8, AN and NAS steel bolts.
Most race car builders are looking for bolts that have some give in
"critical" applications -- bolts/hardware that will stretch rather than
snap, deform and recover rather than disintegrate. Grade 8 bolts are
recommended *against* for high-impact critical applications like
roll-bar mounting for just this reason: Grade 8 bolts are strong but
tend to snap rather than deform, which is exactly wrong for an impact
application.
If you're really interested in understanding this issue, I urge you to
buy/borrow a copy of Carroll Smith's "Nuts, Bolts and Fasteners" (aka
"Screw to Win") and/or "Prepare to Win". There's a good discussion of
the different kinds of hardness grades available, as well as the
metallurgy and thread cutting theory behind them and their application.
The application is *strictly* race cars, and he takes most of his
working knowledge from the aircraft industry. He has no truck with
boats or mundane automotive applications, and doesn't talk about them,
so you'll have to draw your own conclusions about those.
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