A.15° B.30° C.55° D.60°
A.60 B.55 C.30 D.15
A.16mm的粗牙普通螺紋 B.16mm,螺距為1.5mm的左旋細(xì)牙普通螺紋 C.16mm,螺距為1.5mm的細(xì)牙普通螺紋 D.16mm的左旋粗牙普通螺紋