A.0° B.5° C.10° D.15°
A.60° B.75° C.90° D.120°
A.鉆頭不鋒利 B.進(jìn)給量太大 C.切削液選用不當(dāng)或供應(yīng)不足 D.鉆頭太短,排屑槽堵塞