1/2"-13 X 2-1/4", Plow Bolts, Flat Head, #3 Head, Full Thread, Grade 8 Steel, Plain SAE J429
#3 Head Plow Bolts in sizes 3/8 to 5/8 diameters are manufactured to the dimensions specified by ASME/ANSI B18.9 for Regular Head Series.
Two strength levels are available (depending on size and availability):
Grade 5 (per SAE J429) - 120,000 psi minimum Tensile Strength Standard Duty, Good Strength to Toughness Ratio
Grade 8 (per SAE J429) - 150,000 psi minimum Tensile Strength Heavy Duty, Best Strength to Toughness Ratio