1.There are two kinds of gun drills, namely, the center-cut gun drill used for drilling blind holes and the trepanning drill.
深孔钻分为两种，即用于钻削盲孔的中心钻和套孔 钻。
另一方面，直柄钻被固定到钻夹中，同理， 钻夹以与锥柄钻相同的方式固定到主轴孔中。
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1.Twist drills are usually made of high-speed steel, although carbide-tipped drills are also available. The size of twist drills used in industrial range from 0.01 up to 3.25 in. (i.e., 0.25 up to 80 mm).
钻是利用绕轴旋转的钻头在工件上生成通孔或盲 孔的加工工艺。
2.Consequently, the range of cutting from that axis of rotation is equal to the radius of required hole.
因此，旋转轴的切削范围就等于所钻孔的半径。
2.This type of drill may have either three or four flutes and equal number of margins, which ensure superior guidance, thus resulting in high machining accuracy.这种类型的钻具有三个或四个出屑槽以及 相同数量的刃带，这些可确保准确的导向，从而获 得较高的机加工精度。
