机械类车床外文翻译(编辑修改稿)

机械类车床外文翻译(编辑修改稿)内容摘要：

fectly match the external threads on the spindle (two things which almost never happen), an accessory must be used to mount a workpiece to the spindle. A workpiece may be bolted or screwed to a faceplate, a large flat disk that m A workpiece may be clamped in a chuck, which mounts directly to the spindle or mounted on a mandrel. In precision work (and in some classes of repetition work), cylindrical workpieces are invariably held in a collet inserted into the spindle and secured either by a drawbar, or by a collet closing cap on the spindle. Suitable collets may also be used to mount square or hexagonal workpieces. A circular metal plate with even spaced holes around the periphery, mounted to the spindle, is called an index plate. It can be used to rotate the spindle a precise number of degrees, then lock it in place, facilitating repeated auxiliary operations done to the workpiece. Modes of use When a workpiece is supported at both ends, it is more stable may be applied to the workpiece, via tools, at a right angle to the axis of rotation, without fear that the workpiece may break loose. When a workpiece is mounted with a certain axis of rotation, worked, then remounted with a new axis of rotation, this is referred to as eccentric turning or multi axis turning. The result is that various cross sections of the workpiece are rotationally symmetric, but the workpiece as a whole is not rotationally symmetric. This technique is used for camshafts, various types of chair legs, etc. Varieties The smallest lathes are jewelers lathes or watchmaker lathes, which are small enough that they may be held in one hand. Although the workpieces machined on a jeweler39。 s lathes are metal, jeweler39。 s lathes differ from all other metal working lathes in that the cutting tools are hand held and supported by a Trest, not fixed to a cross slide. Two spindle bore sizes to receive the collets are mon, namely 6 mm and 8 mm. Two patterns of bed are mon: the WW (Webs。