actualy I don't think any bolts use that scale as hardness is not the only factor in the strength of any alloyed steel. I was a partener in a small machine shop way back and learned that there are well over a thosand different alloys used in steel that controlled abrasion resistance,ability to take impact, shear strengh and so on. metric bolts have a number stamped on the end denoteing hardness or tuffness as american bolts are stamped with varering numbers of crossing lines like a star for classing them.
You can find fastener shops in any larger city that will have a selection of bolt and fastners from bridge sized to tiny.........
Last edited by william rogers; 09-10-2003 at 05:54 PM.