THE LATHE — PLANING MACHINES — THE STEAM HAMMER — HYDRAULIC TOOLS — ELECTRICAL TOOLS IN THE SHIPYARD
"When I first entered this city," said Mr. William Fairbairn, in an inaugural address to the British Association at Manchester in 1861, "the whole of the machinery was executed by hand. There were neither planing, slotting, nor shaping machines, and with the exception of very imperfect lathes and a few drills, the preparatory operations of construction were effected entirely by the hands of the workmen. Now, everything is done by machine tools, with a degree of accuracy which the unaided hand could never accomplish. The automaton, or self-acting, machine tool has within itself an almost creative power; in fact, so great are its powers of adaptation, that there is no operation of the human hand that it does not imitate."
If such things could be said with justice forty-five years ago, what would Mr. Fairbairn think could he see the wonderful machinery with which the present-day workshop is equipped—machinery as relatively superior to the devices he speaks of as they were superior to the unaided efforts of the human hand? Invention never stands still. The wonder of one year is on the scrap-heap of abandoned machines almost before another twelve months have passed. Some important detail has been improved, to secure ease or economy in working, and a more efficient successor steps into its place. In his curious and original Erewhon, Mr. Samuel Butler depicts a community which, from the fear that machinery should become too ingenious, and eventually drain away man's capacity for muscular and mental action, has risen in revolt against the automaton, broken up all machines which had been in use for less than 270 years—with the exception of specimens reserved for the national museums—and reverted to hand labour. His treatment of the dangers attending the increased employment of lifeless mechanisms as a substitute for physical effort does not, however, show sympathy with the Erewhonians; since their abandonment of invention had obviously placed them at the mercy of any other race retaining the devices so laboriously perfected during the ages. And we, on our part, should be extremely sorry to part with the inanimate helpers which in every path of life render the act of living more comfortable and less toilsome.
So dependent are we on machinery, that we owe a double debt to the machines which create machines. A big factory houses the parents which send out their children to careers of usefulness throughout the world. We often forget, in our admiration of the offspring, the source from which they originated. Our bicycles, so admirably adapted to easy locomotion, owe their existence to a hundred delicate machines. The express engine, hurrying forward over the iron way, is but an assemblage of parts which have been beaten, cut, twisted, planed, and otherwise handled by mighty machines, each as wonderful as the locomotive itself. But then, we don't see these.
This and following chapters will therefore be devoted to a few peeps at the great tools employed in the world's workshops.
If you consider a moment, you will soon build up a formidable list of objects in which circularity is a necessary or desirable feature—wheels, shafts, plates, legs of tables, walking-sticks, pillars, parts of instruments, wire, and so on. The Hindu turner, whose assistant revolves with a string a wooden block centred between two short spiked posts let into the ground, while he himself applies the tool, is at one end of the scale of lathe users; at the other, we have the workman who tends the giant machine slowly shaping the exterior of a 12-inch gun, a propeller shaft, or a marble column. All aim at the same object—perfect rotundity of surface.
The artisans of the Middle Ages have left us, in beautiful balusters and cathedral screens, ample proofs that they were skilled workmen with the Turning-Lathe. At the time of the Huguenot persecutions large numbers of French artificers crossed the Channel to England, bringing with them lathes which could cut intricate figures by means of wheels, eccentrics and other devices of a comparatively complicated kind. The French had undoubtedly got far ahead of the English in this branch of the mechanical arts, owing, no doubt, to the fact that the French noblesse had condescended to include turnery among their aristocratic hobbies.
With the larger employment of metal in all industries the need for handling it easily is increased. Much greater accuracy generally distinguishes metal as compared with woodwork. "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."[5]
Any modern worker is spared this labour and worry by the device known as the Slide-Rest. Its name implies that it at once affords a rigid support for the tool, and also the means of traversing the tool in a straight line parallel to the metal face on which work is being done.
The introduction of the slide-rest is due to the ingenuity of Mr. Henry Maudslay, who, at the commencement of the nineteenth century, was a foreman in the workshop of Mr. Joseph Bramah, inventor of the famous hydraulic press and locks which bear his name. His rest could be moved along the bed of the lathe by a screw, and clamped in any position desired. Fellow-workmen at first spoke derisively of "Maudslay's go-cart"; but men competent to judge its real value had more kindly words to say concerning it, when it had been adapted to machines of various types for planing as well as turning. Mr. James Nasmyth went so far as to state that "its influence in improving and extending the use of machinery has been as great as that produced by the improvement of the steam-engine in respect to perfecting manufactures and extending commerce, inasmuch as without the aid of the vast accession to our power of producing perfect mechanism which it at once supplied, we could never have worked out into practical and profitable forms the conceptions of those master minds who, during the last half century, have so successfully pioneered the way for mankind. The steam-engine itself, which supplies us with such unbounded power, owes its present perfection to this most admirable means of giving to metallic objects the most precise and perfect geometrical forms. How could we, for instance, have good steam-engines if we had not the means of boring out a true cylinder, or turning a true piston-rod, or planing a valve face? It is this alone which has furnished us with the means of carrying into practice the accumulated results of scientific investigation on mechanical subjects."