On Fri, 9 Jun 2017 18:02:30 -0500, DougC
wrote:
In the US, normal stainless bolts are mostly 304 and
extra-corrosion-resistant (marine-grade) ones are 316:
https://en.wikipedia.org/wiki/Stainless_steel

A little more on stainless:

A2 is the same as 304.
A4 is the same as 316 and contains molybdenum and more nickel and
nitrogen making it stronger and more resistant to corrosion.

You can easily tell the difference. A2 is slightly magnetic, while A4
is non-magnetic:
https://www.youtube.com/watch?v=mbbXvvpoLCo

Stainless fasteners are normally NOT coated because stainless is
protected by a thin chromium oxide layer that forms on the surface.

If this is for your bicycle, either stainless type will work. I would
not recommend hot dip galvanized (ugly and too thick), electroplated
zinc (too thin and rusts where scratched), or chrome plating (looks
good until it rusts) fasteners. I'm undecided on bright chrome
plating, which seems to survive fairly well. However, at the small
differential in cost, stainless is still the best.



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Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558