http://www.americanfastener.com/astm-sae-and-iso-grade-markings-for-steel-fasteners/
Rusty shackleford Member Joined Oct 13, 2016 Messages 93 Age 35 Location Los Angeles Jan 9, 2018 #2 http://www.americanfastener.com/astm-sae-and-iso-grade-markings-for-steel-fasteners/