as stated perviously in this thread the ASTM A490's commonly known as the grade 8 are designed for clamping force and is very strong if used in this way, the A490s are a high carbon steel with high yeild resulting in a less maluable/ductile steel with a very fine grain structure. when used in a clamping they are king, but due to thier extream hardness they remain brittle and a shear type force will break them. The A325s or grade 5 have a lesser tensile strenght but are more ductile and will handle shearing better..:c: