Hex bolts, Zinc plated grade 5 steel
Grade 5 hex bolt

Hex bolt diameter is measured on the outside of the threads.

Hex bolt diameter

Diameter and Thread count

1/4"-20 5/16"-18 3/8"-16 7/16"-14 1/2"-13 9/16"-12 5/8"-11 3/4"-10 7/8"-9 1"-8 1-1/4"-7 1-1/2"-6

1/4"-28 5/16"-24 3/8"-24 7/16"-20 1/2"-20 9/16"-18 5/8"-18 3/4"-16

See also
Metric hex bolt

Metric hex bolts

A bolt with a six sided head.