Steel grades for bolts?

"Konstantin Shemyak" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I snapped a head off an allen bolt -- much easier than I'd
expect. It was fixing a rack; and I don't want my stem
bolts to be that weak! How to get any idea about their
quality to buy the correct ones?

Some bolts from my toolbox have marks on their heads,
like: "SBE 8.8", "FS A2-70". Does it indicate steel grade?
Web search on these abbreviations did not return anything.
Generally, any pointers to the "bolt science" are
appreciated.

sizes.combolts SAEtork.htmOpen ↗

Avoid "Grade 8" bolts. If you need a graded bolt use
aircraft certified bolts generally available surplus from
many sources. But they aren't metric. If you want the best
Allen bolts buy them from the Allen folks.After all, they
invented them. It's hard to believe that you cound apply
enough torque to a rack bolt-usually a 5mm-to snap the head
off without stripping the fitting you were screwing it into.
Phil Brown

On Sat, 26 Jun 2004 18:07:35 GMT, Konstantin Shemyak <[email hidden]>

Quoted message said:

I snapped a head off an allen bolt -- much easier than I'd
expect. It was fixing a rack; and I don't want my stem
bolts to be that weak! How to get any idea about their
quality to buy the correct ones?

Some bolts from my toolbox have marks on their heads, like:
"SBE 8.8", "FS A2-70". Does it indicate steel grade? Web
search on these abbreviations did not return anything.
Generally, any pointers to the "bolt science" are
appreciated.

Metric bolts marked 8.8 which actually meet that spec are
roughly the equivalent of an SAE Grade 5, which is good but
fairly ordinary. Unfortunately, such markings are not
reliable; there is a lot of hardware on the market which
bears fraudulent grade markings, both in metric and SAE
sizes. A metric fastener from a known reliable source which
bears a 10.9 marking should be good stuff; if it's up to
spec for that marking, it will be capable of developing
tensions that would typically shear threads from a tapped
hole in an aluminum part before the bolt would break.

As for the "FS A2-70" markings, those are not from a system
with which I'm familiar.
--
Typoes are a feature, not a bug. Some gardening required to
reply via email. Surrealism is a pectinated ranzel.

Konstantin Shemyak said:

like: "SBE 8.8", "FS A2-70". Does it indicate steel grade?

No URLs at hand, unfortunately. 8.8 rates the mechanical
strength and is for fairly standard bolts etc. 10.9 and 12.2
are the better ratings. A2 indicates a rust-free bolt. I am
not sure whether higher grades (A4) are for higher strength
or better resistance to corrosion - the latter, I suppose.

Patrick

That's 10.9 and 12.9 ... typical grade markings for metric
bolts. First number is nominal ultimate tensile strength and
second is % UTS that yield occurs IIRC.

5.8 is roughtly equiv of SAE grade 2, 8.8 is roughly equiv
of SAE grade 5 and 10.9 roughly equiv of SAE grade 8 IIRC

The higher grades are stronger, and will require higher
tigtening torques upon installation. For better corrosion
resistance look at stainless steel, (A2 is equiv of 304
stainless, A4 is equiv of 316 stainless) but the stainless
will be much lower strength (maybe like a 5.8 or 8.8?)

You might call Metric Screw and Tool, Wakefield, MA metricscrew-metricscrew-Open ↗
toolco.com/ (or Maryland Metric mdmetric.commdmetric.comOpen ↗ ) for
more info and catalog.

"Patrick Hansmeier" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Konstantin Shemyak said:

like: "SBE 8.8", "FS A2-70". Does it indicate steel
grade?

No URLs at hand, unfortunately. 8.8 rates the mechanical
strength and is for fairly standard bolts etc. 10.9 and
12.2 are the better ratings. A2 indicates a rust-free
bolt. I am not sure whether higher grades (A4) are for
higher strength or better resistance to corrosion - the
latter, I suppose.

Patrick

[QUOTE]Originally posted by The Masked Marv
[B]That's 10.9 and 12.9 ... typical grade markings for metric
bolts. First number is nominal ultimate tensile strength and
second is % UTS that yield occurs IIRC.

5.8 is roughtly equiv of SAE grade 2, 8.8 is roughly equiv
of SAE grade 5 and 10.9 roughly equiv of SAE grade 8 IIRC

The higher grades are stronger, and will require higher
tigtening torques upon installation. For better corrosion
resistance look at stainless steel, (A2 is equiv of 304
stainless, A4 is equiv of 316 stainless) but the stainless
will be much lower strength (maybe like a 5.8 or 8.8?)

You might call Metric Screw and Tool, Wakefield, MA metricscrew-metricscrew-Open ↗
toolco.com/ (or Maryland Metric mdmetric.commdmetric.comOpen ↗ ) for
more info and catalog.

"Patrick Hansmeier" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Konstantin Shemyak said:

like: "SBE 8.8", "FS A2-70". Does it indicate steel
grade?

No URLs at hand, unfortunately. 8.8 rates the mechanical
strength and is for fairly standard bolts etc. 10.9 and
12.2 are the better ratings. A2 indicates a rust-free
bolt. I am not sure whether higher grades (A4) are for
higher strength or better resistance to corrosion - the
latter, I suppose.

Patrick [/B]