A in-16 UNF series SAE grade 5 bolt has a -in ID tube 13 in

A ¾ in-16 UNF series SAE grade 5 bolt has a ¾ -in ID tube 13 in long, clamped between washer faces of bolt and nut by turning the nut snug and adding one-third of a turn. The tube OD is the washer-face diameter dw = 1.5d = 1.5(0.75) = 1.125 in = OD.