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首页 » 经典英文小说 » The Economy of Workshop Mainipulation » CHAPTER XXXVIII. GAUGING IMPLEMENTS.
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CHAPTER XXXVIII. GAUGING IMPLEMENTS.
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Among the improvements in machine fitting which have in recent years come into general use, is the employment of standard gauges1, by means of which uniform dimensions are maintained, and within certain limits, an interchange of the parts of machinery2 is rendered possible.

Standard gauging3 implements4 were introduced about the year 1840, by the celebrated6 Swiss engineer, John G. Bodmer, a [148]man who for many reasons deserves to be considered as the founder7 of machine tool manufacture. He not only employed gauges in his works to secure duplicate dimensions, but also invented and put in use many other reforms in manipulation; among these may be mentioned the decimal or metrical division of measures, a system of detail drawings classified by symbols, the mode of calculating wheels by diametric pitch, with many other things which characterise the best modern practice.

The importance of standard dimensions, and the effect which a system of gauging may have in the construction of machines, will be a matter of some difficulty for a learner to understand. The interchangeability of parts, which is the immediate8 object in employing gauges, is plain enough, and some of the advantages at once apparent, yet the ultimate effects of such a system extend much farther than will at first be supposed.

The division of labour, that system upon which we may say our great industrial interests are founded, is in machine fitting promoted in a wonderful degree by the use of gauging implements. If standard dimensions can be maintained, it is easy to see that the parts of a machine can be constructed by different workmen, or in different shops, and these parts when assembled all fit together, without that tedious and uncertain plan of try-fitting which was once generally practised. There are, it is true, certain kinds of fitting which cannot well be performed by gauges; moving flat surfaces, such as the bearings of lathe9 slides or the faces of steam engine valves, are sooner and better fitted by trying them together and scraping off the points of contact; but even in such cases the character of the work will be improved, if one or both surfaces have been first levelled by gauging or surface plates.

In cylindrical10 fitting, which as before pointed11 out, constitutes the greater part in machine fitting, gauges are especially important, because trial-fitting is in most cases impossible.

Flat or plane joints12 nearly always admit of adjustment between the fitted surfaces; that is, the material scraped or ground away in fitting can be compensated14 by bringing the pieces nearer together; but parallel cylindrical joints cannot even be tried together until finished, consequently, there can be nothing cut away in trying them together. Tapering15, or conical joints, can of course be trial-fitted, and even parallel fits are sometimes made by trial, but it is evident that the only material that can [149] be cut away in such cases, is what makes the difference between a fit too close, and one which will answer in practice.

As to the practical results which may be attained16 by a gauging system, it may be said that they are far in advance of what is popularly supposed, especially in Europe, where gauges were first employed.

The process of milling, which has been so extensively adopted in the manufacture of guns, watches, sewing-machines, and similar work in America, has, on principles explained in the chapter on milling, enabled a system of gauging which it is difficult to comprehend without seeing the processes carried on. And so important is the effect due to this duplicating or gauging system, that several important branches of manufacture have been controlled in this way, when other elements of production, such as the price of labour, rent, interest, and so on, have been greatly in favour of countries where the trying system is practised.

As remarked, the gauging system is particularly adapted to, or enabled by milling processes, and of course must have its greatest effect in branches of work directed to the production of uniform articles, such as clocks, watches, sewing-machines, guns, hand tools, and so on. That is, the direct effect on the cost of processes will be more apparent and easily understood in such branches of manufacture; yet in general engineering work, where each machine is more or less modified, and made to special plans, the commercial gain resulting from the use of gauges is considerable.

In respect to repairing alone, the consideration of having the parts of machinery fitted to standard sizes is often equal to its whole value.

Machinery subjected to destructive wear, and to be operated at a distance from machine shops—locomotive engines for example—if not constructed with standard dimensions, may, by the detention17 due to repairing, cause a loss and inconvenience equal to their value; if a shaft18 wheel bearing, or even a fitted screw bolt is broken, time must be allowed to make the parts new; and in order to fit them, the whole machine, or such of its details as have connection with the broken parts, must be taken to a shop in order to fit by trial.

The duplicate system has gradually made its way in locomotive engineering, and will no doubt extend to the whole of [150] railway equipment, as constants for dimensions are proved and agreed upon.

The gauging system has been no little retarded19 by a selfish and mistaken opinion that an engineering establishment may maintain peculiar20 standards of its own; in fact, relics21 of this spirit are yet to be met with in old machines, where the pitch of screw-threads has been made to fractional parts of an inch, so that engineers, other than the original makers22, could not well perform repairing, or replace broken parts.

One of the effects of employing gauges in machine fitting is to inspire confidence in workmen. Instead of a fit being regarded as a mysterious result more the work of chance than design, men accustomed to gauges come to regard precision as something both attainable23 and indispensable. A learner, after examining a set of well fitted cylindrical gauges, will form a new conception of what a fit is, and will afterwards have a new standard fixed24 in his mind.

The variation of dimensions which are sensible to the touch at one ten-thousandth part of an inch, furnishes an example of how important the human senses are even after the utmost precision attainable by machine action. Pieces may pass beneath the cutters of a milling machine under conditions, which so far as machinery avails will produce uniform sizes, yet there is no assurance of the result until the work is felt by gauges.

The eye fails to detect variations in size, even by comparison, long before we reach the necessary precision in common fitting. Even by comparison with figured scales or measuring with rules, the difference between a proper and a spoiled fit is not discernible by sight.

Many of the most accurate measurements are, however, performed by sight, with vernier calipers25 for example, the variation being multiplied hundreds or thousands of times by mechanism26, until the least differences can be readily seen.

In multiplying the variations of a measuring implement5 by mechanism, it is obvious that movable joints must be employed; it is also obvious that no positive joint13, whether cylindrical or flat, could be so accurately27 fitted as to transmit such slight movement as occurs in gauging or measuring. This difficulty is in most measuring instruments overcome by employing a principle not before alluded28 to, but common in many machines, that of elastic29 [151] compensation.

A pair of spring calipers will illustrate30 this principle. The points are always steady, because the spring acting31 continually in one direction compensates32 the loose play that may be in the screw. In a train of tooth wheels there is always more or less play between the teeth; and unless the wheels always revolve33 in one direction, and have some constant resistance offered to their motion, 'backlash' or irregular movement will take place; but if there is some constant and uniform resistance such as a spring would impart, a train of wheels will transmit the slightest motion throughout.

The extreme nicety with which gauging implements are fitted seems at first thought to be unnecessary, but it must be remembered that a cylindrical joint in ordinary machine fitting involves a precision almost beyond the sense of feeling, and that any sensible variation in turning gauges is enough to spoil a fit.

Opposed to the maintenance of standard dimensions are the variations in size due to temperature. This difficulty applies alike to gauging implements and to parts that are to be tested; yet in this, as in nearly every phenomenon connected with matter, we have succeeded in turning it to some useful purpose. Bands of iron, such as the tires of wheels when heated, can be 'shrunk' on, and a compressive force and security attained, which would be impossible by forcing the parts together both at the same temperature. Shrinking has, however, been almost entirely34 abandoned for such joints as can be accurately fitted.

(1.) How may gauging implements affect the division of labour?—(2.) In what way do standard dimensions affect the value of machinery?—(3.) Why cannot cylindrical joints be fitted by trying them together?—(4.) Under what circumstances is it most important that the parts of machinery should have standard dimensions?—(5.) Which sense is most acute in testing accurate dimensions?—(6.) How may slight variations in dimensions be made apparent to sight?



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1 gauges 29872e70c0d2a7366fc47f04800f1362     
n.规格( gauge的名词复数 );厚度;宽度;标准尺寸v.(用仪器)测量( gauge的第三人称单数 );估计;计量;划分
参考例句:
  • A thermometer gauges the temperature. 温度计可测量温度。 来自《简明英汉词典》
  • The fuel gauges dropped swiftly. 燃料表指针迅速下降。 来自《简明英汉词典》
2 machinery CAdxb     
n.(总称)机械,机器;机构
参考例句:
  • Has the machinery been put up ready for the broadcast?广播器材安装完毕了吗?
  • Machinery ought to be well maintained all the time.机器应该随时注意维护。
3 gauging 43b7cd74ff2d7de0267e44c307ca3757     
n.测量[试],测定,计量v.(用仪器)测量( gauge的现在分词 );估计;计量;划分
参考例句:
  • The method is especially attractive for gauging natural streams. 该方法对于测量天然的流注具有特殊的吸引力。 来自辞典例句
  • Incommunicative as he was, some time elapsed before I had an opportunity of gauging his mind. 由于他不爱说话,我过了一些时候才有机会探测他的心灵。 来自辞典例句
4 implements 37371cb8af481bf82a7ea3324d81affc     
n.工具( implement的名词复数 );家具;手段;[法律]履行(契约等)v.实现( implement的第三人称单数 );执行;贯彻;使生效
参考例句:
  • Primitive man hunted wild animals with crude stone implements. 原始社会的人用粗糙的石器猎取野兽。 来自《现代汉英综合大词典》
  • They ordered quantities of farm implements. 他们订购了大量农具。 来自《现代汉英综合大词典》
5 implement WcdzG     
n.(pl.)工具,器具;vt.实行,实施,执行
参考例句:
  • Don't undertake a project unless you can implement it.不要承担一项计划,除非你能完成这项计划。
  • The best implement for digging a garden is a spade.在花园里挖土的最好工具是铁锹。
6 celebrated iwLzpz     
adj.有名的,声誉卓著的
参考例句:
  • He was soon one of the most celebrated young painters in England.不久他就成了英格兰最负盛名的年轻画家之一。
  • The celebrated violinist was mobbed by the audience.观众团团围住了这位著名的小提琴演奏家。
7 Founder wigxF     
n.创始者,缔造者
参考例句:
  • He was extolled as the founder of their Florentine school.他被称颂为佛罗伦萨画派的鼻祖。
  • According to the old tradition,Romulus was the founder of Rome.按照古老的传说,罗穆卢斯是古罗马的建国者。
8 immediate aapxh     
adj.立即的;直接的,最接近的;紧靠的
参考例句:
  • His immediate neighbours felt it their duty to call.他的近邻认为他们有责任去拜访。
  • We declared ourselves for the immediate convocation of the meeting.我们主张立即召开这个会议。
9 lathe Bk2yG     
n.车床,陶器,镟床
参考例句:
  • Gradually she learned to operate a lathe.她慢慢地学会了开车床。
  • That lathe went out of order at times.那台车床有时发生故障。
10 cylindrical CnMza     
adj.圆筒形的
参考例句:
  • huge cylindrical gas tanks 巨大的圆柱形贮气罐
  • Beer cans are cylindrical. 啤酒罐子是圆筒形的。
11 pointed Il8zB4     
adj.尖的,直截了当的
参考例句:
  • He gave me a very sharp pointed pencil.他给我一支削得非常尖的铅笔。
  • She wished to show Mrs.John Dashwood by this pointed invitation to her brother.她想通过对达茨伍德夫人提出直截了当的邀请向她的哥哥表示出来。
12 joints d97dcffd67eca7255ca514e4084b746e     
接头( joint的名词复数 ); 关节; 公共场所(尤指价格低廉的饮食和娱乐场所) (非正式); 一块烤肉 (英式英语)
参考例句:
  • Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
  • Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。
13 joint m3lx4     
adj.联合的,共同的;n.关节,接合处;v.连接,贴合
参考例句:
  • I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤,肩膀脫臼了。
  • We wrote a letter in joint names.我们联名写了封信。
14 compensated 0b0382816fac7dbf94df37906582be8f     
补偿,报酬( compensate的过去式和过去分词 ); 给(某人)赔偿(或赔款)
参考例句:
  • The marvelous acting compensated for the play's weak script. 本剧的精彩表演弥补了剧本的不足。
  • I compensated his loss with money. 我赔偿他经济损失。
15 tapering pq5wC     
adj.尖端细的
参考例句:
  • Interest in the scandal seems to be tapering off. 人们对那件丑闻的兴趣似乎越来越小了。
  • Nonproductive expenditures keep tapering down. 非生产性开支一直在下降。
16 attained 1f2c1bee274e81555decf78fe9b16b2f     
(通常经过努力)实现( attain的过去式和过去分词 ); 达到; 获得; 达到(某年龄、水平、状况)
参考例句:
  • She has attained the degree of Master of Arts. 她已获得文学硕士学位。
  • Lu Hsun attained a high position in the republic of letters. 鲁迅在文坛上获得崇高的地位。
17 detention 1vhxk     
n.滞留,停留;拘留,扣留;(教育)留下
参考例句:
  • He was kept in detention by the police.他被警察扣留了。
  • He was in detention in connection with the bribery affair.他因与贿赂事件有牵连而被拘留了。
18 shaft YEtzp     
n.(工具的)柄,杆状物
参考例句:
  • He was wounded by a shaft.他被箭击中受伤。
  • This is the shaft of a steam engine.这是一个蒸汽机主轴。
19 retarded xjAzyy     
a.智力迟钝的,智力发育迟缓的
参考例句:
  • The progression of the disease can be retarded by early surgery. 早期手术可以抑制病情的发展。
  • He was so slow that many thought him mentally retarded. 他迟钝得很,许多人以为他智力低下。
20 peculiar cinyo     
adj.古怪的,异常的;特殊的,特有的
参考例句:
  • He walks in a peculiar fashion.他走路的样子很奇特。
  • He looked at me with a very peculiar expression.他用一种很奇怪的表情看着我。
21 relics UkMzSr     
[pl.]n.遗物,遗迹,遗产;遗体,尸骸
参考例句:
  • The area is a treasure house of archaeological relics. 这个地区是古文物遗迹的宝库。
  • Xi'an is an ancient city full of treasures and saintly relics. 西安是一个有很多宝藏和神圣的遗物的古老城市。
22 makers 22a4efff03ac42c1785d09a48313d352     
n.制造者,制造商(maker的复数形式)
参考例句:
  • The makers of the product assured us that there had been no sacrifice of quality. 这一产品的制造商向我们保证说他们没有牺牲质量。
  • The makers are about to launch out a new product. 制造商们马上要生产一种新产品。 来自《简明英汉词典》
23 attainable ayEzj8     
a.可达到的,可获得的
参考例句:
  • They set the limits of performance attainable. 它们确定着可达到的运行限度。
  • If objectives are to be meaningful to people, they must be clear, attainable, actionable, and verifiable. 如果目标对人们是具有意义的,则目标必须是清晰的,能达到的,可以行动的,以及可供检验的。
24 fixed JsKzzj     
adj.固定的,不变的,准备好的;(计算机)固定的
参考例句:
  • Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗?
  • Once the aim is fixed,we should not change it arbitrarily.目标一旦确定,我们就不应该随意改变。
25 calipers calipers     
n.书法,测径器;测径器
参考例句:
  • He picked up the calipers and gauged carefully.他拿起卡钳仔细测量。
  • The carpenter gauged the dowel with calipers.那木匠用卡钳估量暗榫。
26 mechanism zCWxr     
n.机械装置;机构,结构
参考例句:
  • The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
  • The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。
27 accurately oJHyf     
adv.准确地,精确地
参考例句:
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
28 alluded 69f7a8b0f2e374aaf5d0965af46948e7     
提及,暗指( allude的过去式和过去分词 )
参考例句:
  • In your remarks you alluded to a certain sinister design. 在你的谈话中,你提到了某个阴谋。
  • She also alluded to her rival's past marital troubles. 她还影射了对手过去的婚姻问题。
29 elastic Tjbzq     
n.橡皮圈,松紧带;adj.有弹性的;灵活的
参考例句:
  • Rubber is an elastic material.橡胶是一种弹性材料。
  • These regulations are elastic.这些规定是有弹性的。
30 illustrate IaRxw     
v.举例说明,阐明;图解,加插图
参考例句:
  • The company's bank statements illustrate its success.这家公司的银行报表说明了它的成功。
  • This diagram will illustrate what I mean.这个图表可说明我的意思。
31 acting czRzoc     
n.演戏,行为,假装;adj.代理的,临时的,演出用的
参考例句:
  • Ignore her,she's just acting.别理她,她只是假装的。
  • During the seventies,her acting career was in eclipse.在七十年代,她的表演生涯黯然失色。
32 compensates 66643d75881387c68c4962ba4b92c1c9     
补偿,报酬( compensate的第三人称单数 ); 给(某人)赔偿(或赔款)
参考例句:
  • The company compensates her for extra work. 公司因她的额外工作而给她报酬。
  • A vertical spring compensates for the weight of the sensing element. 用一根垂直弹簧补偿敏感元件的负荷。
33 revolve NBBzX     
vi.(使)旋转;循环出现
参考例句:
  • The planets revolve around the sun.行星绕着太阳运转。
  • The wheels began to revolve slowly.车轮开始慢慢转动。
34 entirely entirely     
ad.全部地,完整地;完全地,彻底地
参考例句:
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。


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