A.0.1~0.2mmB.1~2mmC.0.2~0.4mmD.1.2~1.6mm
A.0.1~0.2mmB.1.2~1.6mmC.0.2~0.4mmD.1.6~2.0mm
A.十字超前刃合金钎头B.平头柱齿钻头C.半球形柱齿钻头D.球墨铸铁钻头