... support disposed between the percussion drill and a stationary forward end drill rod support.(1)Material/Grade:DIN CK45, JIS S45C ... , JIS S20C, SAE1020, AISI1020, ASTM A106B, ASTM A53B, ST45, ST42.(2)Out diameter: hex.19mm, hex.22mm ,hex.28mm , hex.32mm ... hole Drill Bit(1)Diameter:38mm-70mm.(2) shape, carbide 3-blade type , steel cross bit , carbide cross bit ,button bit andetc(3 ...