Originally Posted by
Mechie3
I spent some time this morning and last night looking up grade 8. I don't have access to the SAE standard (not paying $70 for it), but the generic specs of Grade 8
SAE J429 Grade 8
Tensile Strength: 150,000 PSI minimum
Proof Strength: 120,000 PSI
Yield Strength: 130,000 PSI minimum
Hardness: HRC 33-39
I can get 4142 (ETD-150) which has a strength of 130k. Grade 8 doesn't specify material, only those specs, which can be obtained through various material and heat treating combos. I don't have access to heat treating equipment (aside from a torch and bucket of oil which isn't very controlled). I could try to make some from the ETD-150.
there's also an argument that grade 8 should be rolled threads vs cut, but found conflicting information of "it's rolled because it's more economical" vs "it's rolled because it's stronger" and, from what I can tell, the SAE spec doesn't actually say.