Grade 5,5.1,5.2 Bolts.

[Gripper42004]

Anybody see these anywhere?or tried them?

http://www.engineersedge.com/hex_bolt_identification.htm

[SqeezeMasterFlash]

I've never seen most of those grades. Looks like the choices of stuff to bend is ever expanding.

[CMunger]

The numbers look pretty similar. I wonder if it's mroe of a manufacturing tolerances thing... Dave was saying how he has some Grade 5's that are harder than other, identifiable by the co initials on the head.

Pexter should likely be able to shed some light on this. He's pretty knowledgable about the grades and such. I think he's out of town for a couple days, though.

[Clay Edgin]

It would seem to me that the average do-it-yourselfer doesn't know the difference between grade 2, 5, and 8 bolts, and would probably not care about the difference between the 5, 5.1, and 5.2. So I would guess that these specific bolts are made for people who know exactly what they need in their particular field and are not widely available at hardware stores. They might have been around for a while and this is the first time any of us have heard of them. Who knows?

Judging from the carbon content of the three different 5.x bolts there, I'd guess the 5.2's and 5.1's are a hair easier to bend than the regular grade 5's. Higher carbon content means that the steel can be hardened to a greater degree. Low carbon steel (the 5.2 bolt) doesn't get as hard after tempering as its grade 5 brother, although I'm not sure what to make of those yield estimates on the site.

In any event, all three bolts are out of my league! Cool find.