Spindles come in several quality ratings and are supported in headstocks by three to five beanings. Since the accuracy of the work done on a lathe depends on the axis of rotation of the spindle holding the workpiece, the spindle and all its accessories must be built and assembled with the greatest possible care.
在床头箱中，主轴由三到五个轴承支撑着，因为车床上工件的精度取决于主轴夹挡的附件的轴心，所以主轴和其它附件都必须尽可能仔细的建造和安装。
Cutting round holes in metal stock is one of the most common operations performed in the machine shop. Very few metal pieces go through a factory without having holes drilled in them. Later operations are often located by referring to these holes. Drilling machines are used to produce most of these holes. They are also used in operations such as reaming, boring, countersinking, counterboring, and tapping.
在金属毛坯上加工圆孔是最常见的金属加工。很少有工件经过工厂没有被钻孔。后续的操作经常是参照这些孔而定位的。钻孔就是用来制造大多数这样的孔的一种机器。
There are several types of mechanisms used to control the speed of a drilling machine. The simplest arrangement utilizes（利用）a belt for transferring power from a four-step, five- step, or six-step V pulley(三角皮带轮) located on the motor to a similar puller attached to the drill press spindle. To increase power on some belt and pulley machines, a counter shaft drive is sometimes added. Another mechanism(原理)used is the variable-speed pulley, which makes it possible to change the machine’s speed without stopping it. In fact, the speed must only be changed while the machine is running. Pulleys of a variable(多变的)-speed drive are made of two parts having V-shaped sides.
有几种机构可以用来控制钻床的速度，最简单的装置就是皮带轮。它可以装在电机上一个四级、五级或六级皮带轮上将动力传到装在钻床主轴上的一个相似的皮带轮上。有时还增加一个中间轴驱动的目的是增加带和带轮机构的动力。另一个原理是应用变速皮带轮，它能在机器运转的时候改变机器的速度。事实上，机器的速度必须在机器运转的情况下改变。变速皮带轮是由两个V型面构成的。
Milling is a process of generating machined surfaces by progressively removing a predetermined amount of material from the workpiece. The process employs relative motion between a workpiece and a rotating cutter to generate the required surface. In some applications, the workpiece is held stationary while the rotating cutter is moved past it at a given feed rate.
铣削是一种逐步去除工件上预定的材料而渐渐形成机加表面的加工方法。它的工艺过程是通过工件和旋转的道具之间的相对运动等形成所需的表面。在一些应用中，工件是固定的，通过刀具在给定速度的运转下完成铣削。
Facing milling is done on both horizontal(水平的)and vertical(竖直的)milling machines. The milled surface resulting from the combined action of cutting edges located on the periphery and the face of the cutter is generally at right angles to the cutter axis(轴). The milled surface is flat , there being no relation to the contour of the teeth, expect when milling to a shoulder. Generally, face milling should be applied wherever and whenever possible.
端铣不仅可以在立式机床上加工，也可以在卧式铣床上加工。由装在外面的道具的刀刃及刀面的联合作用而产生的铣削表面常与刀轴成一直角，铣削表面是平的，与所使用的刀齿的轮廓无关，除非是铣削方向，一般在可能的场合可能的时间尽可能的使用端铣。
The way a grinding(刺耳的)wheel performs depends a good deal on how fast the wheel is turning and how fast the workpiece passes under it. If either the workpiece or the wheel moves too fast, the abrasive grains get very litter chance to do any cutting. In this case, the wheel gives
