Abstract:Because of the lower rock fragmentation efficiency and defective geometrical shape of chisel bit, Sweden has replaced chisel bit with taper connecting cross chisel bit and button bit since the mid seventies. Now, we propose that chisel bit is renewed with more advantageous composite cutter bit gradually. The expected life of new series of bit is 2 to 4 times of that of the chisel bit and button bit, and the price is only one fifth to one third higher than that of chisel bit and button bit.
