Astm A307a

Jack grinned. "Ah, that's the grade. The 'A' indicates that the bolts meet the standard specification for carbon steel bolts, studs, and stud bolts. It's a way to ensure that the bolts are manufactured to a specific standard, so we can trust that they'll perform as expected."

For a 1/2"-13 Grade A bolt, typical installation torque is around 50–70 ft-lbs (compared to 90+ ft-lbs for a Grade 5). Always follow engineering drawings, not guesswork. astm a307a

ASTM A307 Grade A bolts are manufactured from (typically 1018 or similar). There is no mandatory heat treatment, which keeps the manufacturing process simple and the product inexpensive. Jack grinned