Unit 10TEXT READING MATERIAL Unit 10Unit 10TEXTLathe A lathe is a machine tool for cutting metal from the surface of a round work fastened between the two lathe centers and turning around its axis. In turning the work a cutter moves in the direction parallel to the axis of rotation of the work or at an angle to this axis, cutting off the metal from the surface of the work. This movement of the cutter is called the feed. The cutter is clamped in the tool post which is mounted on the carriage. The carriage is the mechanism feeding the cutter in the needed direction. The lathe hand may feed the cutter by hand or may make it be fed automatically by means of special gears. Unit 10 The largest part of the lathe is called the bed on which the headstock and the tailstock are fastened at opposite ends. On the upper part of the bed there are special ways upon which the carriage and the tailstock slide. The two lathe centers are mounted in two spindles: one (the live center) is held in the headstock spindle, while the other (the dead center) in the tailstock spindle. Unit 10Fig. 10-1 An engine latheUnit 10 The lathe chuck is used for chucking the work, which is for clamping it so that it will rotate without wobbling while turning. The chuck, usually, mounted on the headstock spindle, may have different sizes and construction. If the work is perfectly round, it may be chucked in the so-called three-jaw universal chuck, all the jaws of which are moved to the center by turning the screw. But if the work is not perfectly round, the four-jaw independent chuck should be used. In turning different materials and works of different diameters, lathes must be run at different speeds. The gearbox contained in the headstock makes it possible to run the lathe at various speeds.Unit 10 Before turning a work in the lathe, the lathe centers are to be aligned; that means that the axes of both centers must be on one line. The alignment of the lathe centers may be tested by taking a cut and then measuring both ends of the cut with a micrometer.Not all works should be fastened between the two centers of the lathe. A short work may be turned without using the dead center, by simply chucking it properly at the spindle of the headstock. Unit 10LEARN TO SPEAKMr. Li:Excuse me, may I ask you a question? Bob.Bob: Of course!Mr. Li:Do you know about the structure of the lathe?Bob: Yes. I know some of them.Mr. Li:Whats this?Bob: Its a headstock. Sometimes people call it as the heart of a lathe.Mr. Li:Whats this then?Unit 10Bob: Its a chuck and a work-piece can be mounted on it.Mr. Li:Whats that?Bob: Its tool post and carriage. The cutting tools are put here.Mr. Li:Whats that?Bob: Its center and tailstock.Mr. Li:Whats that?Bob: Its a bed. These are all the main structure of the lathe. Are those clear to you?Mr. Li:Yes. You are very kind.Bob: Delighted to have been of assistance. Unit 10NEW WORDS AND EXPRESSIONSdrilling drIlIN n. 钻削milling mIlIN n. 铣削fasten 5fB:s(E)n; (?) fAsn v. (使)固定，加固，连接feed fi:d n.&vt. 进给，送给cutter 5kQtE(r) n. 刀具Unit 10clamp klAmp n. 夹子，夹具，夹钳vt. 夹住，夹紧carriage 5kArIdV n. 溜板，拖板bed bed n. 床，床身headstock hedstBk n. 主轴箱tailstock teIlstBk n. 尾架，尾座，顶针座slide slaId v. (使)滑动，(使)滑行n. 滑动Unit 10metalwork 5met(E)lw:k n. 金属制品，金属制造spindle 5spInd(E)l n. 轴，主轴，连接轴wobble 5wBb(E)l vi. 摇晃，摇摆alignment E5laInmEnt n. 队列，对准，同轴度micrometer maI5krBmItE(r) n. 测微计，千分尺machine tool 机床，工具机milling machine 铣床tool post 刀座，刀架 live center 主轴顶尖dead center 尾架顶尖Unit 10NOTES 1A lathe is a machine tool for cutting metal from the surface of a round work fastened between the two lathe centers and turning around its axis. 车床是用来从圆形工件表面上切除金属的机床，工件安装在车床的两个顶尖之间，并绕顶尖轴线旋转。 “fastened between the two lathe centers”和“turning around its axis”是两个并列的分词短语。“fastened”含有被动的意义，“turning”含有主动的意义，均作定语修饰名词work。 “Its”是指“round work”。 Unit 10 2In turning the work a cutter moves in the direction parallel to the axis of rotation of the work or at an angle to this axis, cutting off the metal from the surface of the work. 车削工件时，车刀沿着工件的旋转轴线平行移动或者是与工件的旋转轴线成一斜角移动，将工件表面的金属切除。 “parallel”为形容词，“parallel to the axis of rotation of work”做后置定语修饰名词“direction”。 “cutting off the metal from the surface of the work”为分词短语作状语，表示伴随情况。这种状语往往放在句末，常用逗号与句子的其它成分隔开。Unit 10 3The lathe hand may feed the cutter by hand or may make it be fed automatically by means of special gears. 用手操纵手柄来使车刀实现进给，也可以借助于专门的传动装置实现自动进给。 有些动词如“make”、“hear”、“let”、“watch”后的不定式作宾语补语时，可不带不定式符号“to”。句中“be fed”是不定式的被动式，作宾语it的补语。由于其谓语动词是“make”，故省略不定式符号“to”，而成为“make it be fed”。这里“it”代表“the cutter”。 句中“the lathe hand”为主语，带有两个并列的谓语“may fed”和“may make”。Unit 10 4The gear box contained in the headstock makes it possible to run the lathe at various speeds. 装入床头箱内的齿轮系统能使车床以不同的速度运转。 “it”在句中作形式宾语，而真正的宾语是不定式短语“to run the lathe at various speeds”。它通常放在宾语补足语(possible)的后面。 “contained in the headstock”作后置定语，修饰名词“the gearbox”。 5before turning a work in the lathe, the lathe centers are to be aligned; that means that the axes of both centers must be on one line.Unit 10 车床在车削工件前