Countersunk head
Raised countersunk head
Countersunk head square neck
Countersunk head with nib
Square countersunk head
Countersunk Cheese head
T-head countersunk
BS 325-4-1947
Black 80° countersunk nibbed bolts and countersunk round bolts-Table 4
BS 325-5-1947
Black 80° countersunk square neck bolts for iron and steel work-Table 5
BS 325-6-1947
Black 110° countersunk square neck bolts for iron and steel work-Table 6
