... 16" 406.4mmPin shank size: 7 5/8regNormal WOB(bit dia): 0.25--0.70KN/mmRotary speed: 200~80r/ ... gypsolyte, soft limestone and sandstone, etc Main characteristics of bit(cutting structure)The back cone and the teeth all ... tooth shape and welding materials.Normal WOB KN/mm (bit dia.)0.25--0.70Rotary speed (rpm)200~80Payment ... 3/410 5/8,12 1/413 3/4, 17 1/2,22, 24,26M223,M322,M316,M222,M416,M122 Petroleum ...