5/16″ UNF x 1-1/2″ Hex

A 1/4 BSF hexagon bolt (part threaded)Under head dimension: 1-1/2". Thread length: 9/16". Standard hexagon size (.445" A/F)Head machined flat (no markings).

A 1/4 BSF hexagon set bolt (threaded up to head)Under head dimension: 3/8". Standard hexagon size (.445" A/F)Head machined flat (no markings).

A 5/16 BSF hexagon bolt (part threaded)Under head dimension: 1-1/2".Thread length: 5/8" Standard hexagon size (.525" A/F)Head machined flat (no markings).

A 5/16 BSF hexagon set bolt (threaded up to head)Under head dimension: 3/4". Standard hexagon size (.525" A/F)Head machined flat (no markings).