ISO 1721:1974, Rock drilling -- Extension drill-steel equipment for percussive long-hole drilling -- Reverse-buttress-threaded equipments 1 1/16 and 1 1/4 in (27 and 32 mm)

Specifies the basic dimensions for equipment. Gives a list of components; tabulates together with figures: shank adapters for central flushing, hexagon type and lug-shank type; extension rods; coupling sleeves; four-wing bits; reverse-buttress threads; hollow hexagonal bars for extension rods; hexagonal drill-steels. This title may contain less than 24 pages of technical content.