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第60章

industrial biography-第60章

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industry; the King might have made from 40s。 to 50s。 a…week as a hard

wood and ivory turner。  Lord John Hay; though one…armed; was an adept

at the latter; and Lord Gray was another capital turner。  Indeed the

late Mr。 Holtzapffel's elaborately illustrated treatise was written

quite as much for amateurs as for working mechanics。  Among other

noble handicraftsmen we may mention the late Lord Douglas; who

cultivated bookbinding。  Lord Traquair's fancy was cutlery; and one

could not come to him in a more welcome fashion than with a pair of

old razors to set up。

 。。。'

There was at that time a great passion for automata in France; which

gave rise to many highly ingenious devices; such as Camus's miniature

carriage (made for Louis XIV。 when a child); Degennes' mechanical

peacock; Vancanson's duck; and Maillardet's conjuror。  It had the

effect of introducing among the higher order of artists habits of

nice and accurate workmanship in executing delicate pieces of

machinery; and the same combination of mechanical powers which made

the steel spider crawl; the duck quack; or waved the tiny rod of the

magician; contributed in future years to purposes of higher

import;the wheels and pinions; which in these automata almost

eluded the human senses by their minuteness; reappearing in modern

times in the stupendous mechanism of our self…acting lathes;

spinning…mules; and steam…engines。



〃In our own country;〃 says Professor Willis; 〃the literature of this

subject is so defective that it is very difficult to discover what

progress we were making during the seventeenth and eighteenth

centuries。〃*

 'footnote。。。

Professor WILLIS; Lectures on the Results of the Great Exhibition of

1851; lst series; p。 306。

 。。。'

We believe the fact to be; that the progress made in England down to

the end of last century had been very small indeed; and that the

lathe had experienced little or no improvement until Maudslay took it

in hand。  Nothing seems to have been known of the slide rest until he

re…invented it and applied it to the production of machinery of a far

more elaborate character than had ever before been contemplated as

possible。  Professor Willis says that Bramah's; in other words

Maudslay's; slide rest of 1794 is so different from that described in

the French 'Encyclopedie in 1772; that the two could not have had a

common origin。  We are therefore led to the conclusion that Maudslay's

invention was entirely independent of all that had gone before; and

that he contrived it for the special purpose of overcoming the

difficulties which he himself experienced in turning out duplicate

parts in large numbers。  At all events; he was so early and zealous a

promoter of its use; that we think he may; in the eyes of all

practical mechanics; stand as the parent of its introduction to the

workshops of England。



It is unquestionable that at the time when Maudslay began the

improvement of machine…tools; the methods of working in wood and

metals were exceedingly imperfect。  Mr。 William Fairbairn has stated

that when he first became acquainted with mechanical engineering;

about sixty years ago; there were no self…acting tools; everything

was executed by hand。  There were neither planing; slotting; nor

shaping machines; and the whole stock of an engineering or machine

establishment might be summed up in a few ill…constructed lathes; and

a few drills and boring machines of rude construction。*

 'footnote。。。

Address delivered before the British Association at Manchester in

1861; and Useful Information for Engineers; 1st series; p。 22。

 。。。'

Our mechanics were equally backward in contrivances for working in

wood。  Thus; when Sir Samuel Bentham made a tour through the

manufacturing districts of England in 1791; he was surprised to find

how little had been done to substitute the invariable accuracy of

machinery for the uncertain dexterity of the human hand。  Steam…power

was as yet only employed in driving spinning…machines; rolling

metals; pumping water; and such like purposes。  In the working of wood

no machinery had been introduced beyond the common turning…lathe and

some saws; and a few boring tools used in making blocks for the navy。

Even saws worked by inanimate force for slitting timber; though in

extensive use in foreign countries; were nowhere to be found in Great

Britain。*

 'footnote。。。

Life of Sir Samuel Bentham; 97…8。

 。。。'

As everything depended on the dexterity of hand and correctness of

eye of the workmen; the work turned out was of very unequal merit;

besides being exceedingly costly。  Even in the construction of

comparatively simple machines; the expense was so great as to present

a formidable obstacle to their introduction and extensive use; and

but for the invention of  machine…making tools; the use of the

steam…engine in the various forms in which it is now applied for the

production of power could never have become general。



In turning a piece of work on the old…fashioned lathe; the workman

applied and guided his tool by means of muscular strength。  The work

was made to revolve; and the turner; holding the cutting tool firmly

upon the long; straight; guiding edge of the rest; along which he

carried it; and pressing its point firmly against the article to be

turned; was thus enabled to reduce its surface to the required size

and shape。  Some dexterous turners were able; with practice and

carefulness; to execute very clever pieces of work by this simple

means。  But when the article to be turned was of considerable size;

and especially when it was of metal; the expenditure of muscular

strength was so great that the workman soon became exhausted。  The

slightest variation in the pressure of the tool led to an

irregularity of surface; and with the utmost care on the workman's

part; he could not avoid occasionally cutting a little too deep; in

consequence of which he must necessarily go over the surface again;

to reduce the whole to the level of that accidentally cut too deep;

and thus possibly the job would be altogether spoiled by the diameter

of the article under operation being made too small for its intended

purpose。



The introduction of the slide rest furnished a complete remedy for

this source of imperfection。  The principle of the invention consists

in constructing and fitting the rest so that; instead of being

screwed down to one place; and the tool in the hands of the workman

travelling over it; the rest shall itself hold the cutting tool

firmly fixed in it; and slide along the surface of the bench in a

direction exactly parallel with the axis of the work。  Before its

invention various methods had been tried with the object of enabling

the work to be turned true independent of the dexterity of the

workman。  Thus; a square steel cutter used to be firmly fixed in a

bed; along which it was wedged from point to point of the work; and

tolerable accuracy was in this way secured。  But the slide rest was

much more easily managed; and the result was much more satisfactory。

All that the workman had to do; after the tool was firmly fitted into

the rest; was merely to turn a screw…handle; and thus advance the

cutter along the face of the work as required; with an expenditure of

strength so slight as scarcely to be appreciable。  And even this

labour has now been got rid of; for; by an arrangement of the

gearing; the slide itself has been made self…acting; and advances

with the revolution of the work in the lathe; which thus supplies the

place of the workman's hand。  The accuracy of the turning done by this

beautiful yet simple arrangement is as mechanically perfect as work

can be。  The pair of steel fingers which hold the cutting tool firmly

in their grasp never tire; and it moves along the metal to be cut

with an accuracy and precision which the human hand; however skilled;

could never equal。



The effects of the introduction of the slide rest were very shortly

felt in all dep

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