"Ed Huntress" wrote in message
...

"Bob La Londe" wrote in message
...
"David Billington" wrote in message
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Bob La Londe wrote:
On 4/11/2011 8:29 PM, Ed Huntress wrote:
"Bob La wrote in message
...
On 4/11/2011 8:17 PM, Bob AZ wrote:
On Apr 11, 8:15 pm, Bob La wrote:
I have need of stainless for various applications and to be frank
the
local stores just don't stock much. The box stores have a modest
selection, but its all no grade listed Hillman crap. Their
stainless is
worse than their packaged screws if that's possible.

I would like to have some idea what to search for for grades
equivalent
to steel grades. Like what stainless bolt would I look for to be
roughly equal to a grade 8 steel bolt? A grade 5? Never mind
grade 2.
Like I said, "the box stores have Hillman crap."

Bob

McMaster-Carr. mcmaster.com

Bob AZ


A search for "grade 8 stainless" on their site only shows hex nuts.
In
the suggested search items it shows 18-8, but does not say if that is
the
same strength as Grade 8 bolts.

It's not. Not even close.

I think that a Grade 8 in stainless is one very special bolt -- either
a
44X-series or a precipitation-hardening grade.


I did find some reference in a UK welding group that seemed to indicate
that A4-80 was close, but the only bolts I've found in that so far are
metric.


IIRC A4 is 316 and those fasteners won't be anywhere near a grade 8.
I've seen someone recently confuse metric 8.8 designation with grade 8,
a big difference. An 8.8 fastener is about the same as a grade 5.

This person claims some, but not all 316 bolts are close, but slightly
less tensile strength than grade 5.
http://reviews.ebay.com/Stainless-Bo...00000001623345

It depends entirely on the degree of work-hardening applied to the bolt,
and there is no standard for designating it. Annealed, 316 has about 30
ksi yield and 75 ksi ultimate tensile strength. (weak for steel)
Cold-drawn wire runs up to 95 ksi ultimate tensile. When you make a bolt
from it, it's generally cold-headed and roll-threaded. The strength varies
all over the bolt because of the uneven cold-working.

You can't heat-treat 316, except to anneal it.

Hi-strength stainless bolts are made from heat-treatable grades, either
400-series (such as 420 or 440), or precipitation-hardening grades (17-4
PH). You can harden 17-4 PH close to 200 ksi tensile. They cost a bundle
compared to ordinary bolts.

Thanks. Sometimes a "Grade 8" is the bolt for the job, and sometimes a
"Grade 5" is better. I was hoping to find an equivalent for both, but that
seems to be not practical. Grade 2 is rarely the best choice except as a
shear bolt on farm equipment. Looks like I have the choice of going with
quality (ARP) or unknown when it comes to stainless but no other way to
grade.