? Flute n.长笛，横笛，凹槽
? 钻头可以定义为具有一个或者多个切削刃的回转刀具，它的一个或多个螺旋排屑槽或直排屑槽起到作为切屑排除通道和容纳切削液的作用。
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Drilling; Reaming; Tapping; Counterboring; Countersinking; Spotfacing; Boring
钻孔、铰孔、攻丝、平底锪孔、锥底锪孔、锪孔口平面、镗孔 幻灯片55
5.4 Drilling and Drill Press
? Drilling
? Drilling involves selecting the proper twist drill or cutter for the job, properly installing the drill into the machine spindle, setting the speed and feed, drilling a smaller pilot hole, and drilling the hole to specifications within the prescribed tolerance. Drilled holes are always slightly oversized, or slightly larger than the diameter of the drill?s original designation.
WHY?
? 钻削时针对不同的工件要选择合适的钻头，将钻头正确的安装在主轴上，设定好速度和进给量，先加工一个小的导向孔，然后加工出满足公差要求的孔。钻削加工出来的孔通常都略大一些，或者说是比原始指定的钻头直径稍大一些。
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5.4 Drilling and Drill Press
? Reaming
? It is difficult, if not impossible, to drill a hole to an exact standard diameter. When great accuracy is required, the holes are fist drilled slightly undersized and then reamed to size.
When you must drill and ream a hole, it is best if the setup is not changed.
? 把孔钻削到准确的标准直径，即使并非不可能，那也是非常困难的。当精度要求很高时， 可以先钻一个小孔，然后通过铰削将孔加工到规定尺寸。
? 当你必须先钻孔再铰孔时，工件最好是一次装卡。
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5.4 Drilling and Drill Press
Tapping is cutting a thread in a drilled hole. 幻灯片58
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5.4 Drilling and Drill Press
? Counterboring
? Counterboring is the process of using a counterbore to enlarge the upper of a hole to a predetermined depth. Countebored holes are primarily used to recess socket head cap screws and similar bolt heads slightly below the surface. ? socket head cap screws 内六角螺钉 bolt heads 螺栓头
? 平底锪钻就是利用平底扩孔钻将孔德上端扩至预定深度。平底锪孔主要用于安放圆柱头内六角螺钉或类似的螺栓头，使其略低于孔平面。
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5.4 Drilling and Drill Press
? Countersinking
Countersinking is an operation in which a cone-shaped enlargement is cut at the top of a hole to form a recess below the surface. A conical cutting tool is used to produce this chamfer. When countersinking, the cutter must be properly aligned with the existing hole. Countersinking is useful in removing burrs from edges of the holes, as well as
accommodating the countersunk screw head. ? cone-shaped adj.锥形的 ? conical adj.圆锥形的 ? chamfer n.斜面、倒角、凹槽 ? burr n.毛刺
? countersunk n.沉头孔、埋头孔
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5.4 Drilling and Drill Press
? Countersinking
? Countersinking is an operation in which a cone-shaped enlargement is cut at the top of a hole to form a recess below the surface. A conical cutting tool is used to produce this chamfer. When countersinking, the cutter must be properly aligned with the existing hole. Countersinking is useful in removing burrs from edges of the holes, as well as accommodating the countersunk screw head.
锥底锪孔就是在孔的顶部扩一个略低于顶面的锥形凹坑。要加工出这个沉头孔需要锥形锪钻（锥形切削刀具） 。锪孔时，锪钻必须与底孔很好的对中。锥形锪孔主要用于去除孔边的毛刺和安放沉头螺钉。
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5.4 Drilling and Drill Press
? Spotfacing
? Spotfacing is the smoothing off and squaring of a rough or curved surface around a hole to permit level seating of washers, nuts, or bolt heads.
When rough surface, castings, and curved surfaces are not at the right angles to the cutting tool, great strain may occur on the pilot hole and counterbore, which can lead to broken tools.
? 锪孔口平面主要是将孔口周围崎岖不平的粗糙表面进行平整加工，用以平整的安放垫圈、螺帽或螺栓头。
? 当加工的是粗糙表面，铸件表面或是曲面时，锪钻与这些表面不能垂直，这样会使导向孔与锪钻之间产生很大的应变，可导致刀具破损。
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5.4 Drilling and Drill Press
? Boring
? Boring is conducted when a straight and smooth hole is needed occasionally which is too large or odd sized for drills or reams. ? To bore accurately, the setup must be rigid, machine must be sturdy, and power feed must be used. ? odd sized 非标准系列尺寸的 sturdy ['st?:di] adj. 结实的，牢固的