Two, can not directly observe the cutting tool.

不能直接观察到刀具的切削情况。

The cutting tool material is best used hard alloy.

刀具材料最好采用硬质合金。

The wear and rupture of cutting tool are investigated.

分析了切削硬岩时的刀具磨损和破损特征。

Danny: By moving a cutting tool against a rotating workpiece.

丹尼：通过将切割刀具移近旋转的工件。

Jigs physically limit and control the path of the cutting tool.

钻模有形地限制和控制钻削刀具的路径。