111mm - 146mm Reverse Circulation Drill Bits , Small Mining Drill Bits

111mm - 146mm Reverse Circulation Drill Bits , Small Mining Drill Bits Description: Bit face shape selection: 1. Drop Center Bit For high penetration rates in soft to medium hard and fissure rock formations. Low to medium air pressures. Maximum hole deviation control. 2. Concave Face The all-round application bit face specifically for medium hard and homo generous rock formations. Good hole deviation control and good flushing capacity. 3. Convex Face For high penetration