... symmetric drilling tools, eccentric drilling tools, standardized API system casings, bit shanks and casing tubes which are fit for hydraulic drilling ... such as electro-hydraulic forging hammer, seal chamber furnace lines, precision machine tools and so on. We adopt numerical control process ... ,R32,R38,T38,T45,T51Face Shape---Plate, Concave, Convex.Bit Shank & Coupling sleeve---R22,R25,R28,R32,R38,T38, ...