what is button bit and insert bit

Insert bits belong to the variety with the longest history, the most comprehensive applications and the largest production in China. Chisel bits are mainly used for small holes and short holes, and cross bits and X type bits for hard long holes. Due to own structure and subjected force, insert bits are low in efficiency of breaking rock, slow in penetration and large in cemented carbide usage causing kind of waste. Furthermore, the maximum diameter is limited. The diameters of common chisel bits are not more than 45mm, the cross bits are not more than 64mm, and the X type bits are not more than 102mm. Otherwise, cemented carbide may crack, which leads to early failure. Except for quarrying operations and some extremely hard rock, insert bits are unable to meet the needs of modern drilling operation. Now, insert bits are being gradually replaced by button bits under many conditions of medium hard and nonabrasive rock.

Button bits are manufactured by embedding carbide buttons on bit bodies. Compared with insert bits, the arrangement of buttons of the button bits are freer, the quantity and the positions of gauge and front buttons can be reasonably determined according to hole diameters and rock conditions, and the diameters of the button bits are not limited. Because of breaking rock from multiple points, the button bits have advantages of high breaking efficiency, effective elimination of blind areas and repeated breakage prevention. In addition, because the abrasion strength of buttons is higher than that of inserts, button bits have longer one-pass life and small regrinding workload, which show higher values under the condition of mechanized drill rigs in long hole drilling. According to the connection with drill rods, button bits can be divided into three categories of tapered bits, threaded bits and DTH bits.