Machination

“ We are able to machine the earth in much the same way as a piece of metal is machined in the machine shop. In fact, the drill, [252] the circular saw, the slotter, and even the milling machine have their counterpart in the excavating machinery of to-day. Of course we cannot expect to find the counterpart of such machines as the lathe, boring mill, and planer, in which the work revolves against the tool, because this planet of ours is rather too big a piece of stock to be placed between lathe centers or to be bolted to a planer bed. ”

“ Such are among the triumphs of modern mechanical engineering, due in a great measure to the perfection of the tools by means of which all works in metal are now fashioned. These tools are themselves among the most striking results of the mechanical invention of the day. They are automata of the most perfect kind, rendering the engine and machine-maker in a great measure independent of inferior workmen. For the machine tools have no unsteady hand, are not careless nor clumsy, do not work by rule of thumb, and cannot make mistakes. ”

“ These men or women (for female labour is employed for polishing) hold the frames on grinding wheels or in some cases endless belts coated with emery, and they grind or polish the whole frame till it is bright and very smooth.
The frames and forks then go to the enamellers, a part of the factory we shall visit presently, when the other parts are ready for the painting process.
The Machine Shop is the department where all the parts that require turning, boring, milling, or profiling, are machined, as the various metal removing processes are termed. ”

“ In a milling machine the cut is carried continuously from its commencement to its end, whereas in a shaping or planing machine the tool does not usually cut during the back or return stroke. In either of these machines, therefore, the operator’s skill is required as much in measuring the work, setting the tools feeds, &c., as in shaping the tools, whereas in the milling machine all the skill required lies in the chucking and adjustment of the work to the cutter, rather than in operating the machine, which may therefore be operated by comparatively unskilled labor. ”

“ We find, too, that on quantity production in toolroom, we are in a position to effect some very great savings in time and money, as it permits standard jigs and fixtures, such as in ordinary manufacturing; for instance, we at one time machined all our flat tool bits made of high speed steel before hardening and grinding, while our present method is to heat bars of steel in gas furnace and then punch out with die under heavy hammer or press. This method alone in a couple of hours gives us a supply ahead that would ordinarily take one machine or more in continuous operation to produce. ”

“ The word is also applied to many mechanical devices by which raw material is transformed into a condition ready for use or into a stage preparatory to other processes, e.g. saw-mill, rolling-mill, &c., or still more widely to buildings containing machinery used in manufactures, e.g. cotton-mill. In mining it is applied to various machines used in breaking and crushing the ore (see Ore-Dressing) .
In the engineering industries milling machines constitute a very important class of machine tools, the characteristic of which is that rotary cutters are employed for shaping the metal (see Tools) . ”

“ There is no trade or occupation which calls forth the inventive faculty to a greater degree than the machinist's. Whether it be in the direction of making some new tool, needed in some special work, or in devising a particular movement, or mechanical expedient, the machinist must be prepared to meet the issues and decide on the best structural arrangement.
Opportunities also come daily to the workers in machine shops to a greater extent than other artisans, because inventors in every line bring inventions to them to be built and experimentally tested. ”

“ All holes are cast and come out smoother than they could be reamed; lugs and gear teeth are cast in place; threads, external and internal, and of any desired pitch can be cast. Oil grooves can be cast in bearings, and, in a word, any piece that can be machined can be die-cast.
The saving in machining works both ways; not only is all machine work eliminated by the one operation of casting, but the machine tools and the workmen necessary for their operation and up-keep are dispensed with, the expense of building jigs and fixtures is stopped ”

“ The extended use of the milling machine, which is an especial feature of modern machine shop practice, is due, in a very large degree, to the solid emery wheel, which provides a simple method of sharpening the cutters without requiring them to be annealed and rehardened, it being found that annealing and rehardening reduces the cutting qualifications of the steel, and also impairs the truth of the cutting edges by reason of the warping or distortion that accompanies the hardening process. ”

“ The real problem is how to remove chips fast from a casting or a forging, and how to make the piece smooth and true in the shortest time, and it matters but little whether the piece being worked upon is part, say, of a marine engine, a printing-press, or an automobile. For this reason, the man with the slide-rule, familiar with the science of cutting metals, who had never before seen this particular work, was able completely to distance the skilled mechanic who had made the parts of this machine his specialty for years. ”

“ To coördinate a number of inanimate pieces of steel and iron, to operate at high speed with precision, requires fine skill. The evolution from the first cutting machine—the old hand-operated wooden plough and press—to the present power-driven steel mechanism is like the advance from the old wooden sailing vessel to the modern steel ship. ”

“ There is no economy in making men work with poor light, bad air and in a cold place.
Buying Machine Tools.—Having secured by lease or by purchase a shop, or factory suitably located your next effort will be directed toward equipping it with the proper tools and machinery.
Besides the usual machinists’ hand tools you should buy (1) a gas furnace; (2) a grinder; (3) a plain lathe; (4) a screw cutting lathe; (5) a drill press; (6) a planer; (7) a shaper; (8) perhaps a milling machine, and (9) a buffer. Several of each of these kinds of machines may be needed.
Fig. ”

“ A skilled mechanic sets the machine and the chucks which hold the work; an unskilled hand can continue the operations, his products being uniformly of the dimensions and forms desired. Intricate shapes are easily executed, quite impracticable on any other machine. At first the revolving mechanism and its cutters were a single piece of metal; to-day cutters of costly quality are inserted in cheap metal; these inserted cutters when worn out are easily replaced.
[99]
Iron planer; a, b, c, d, fixed cutting tools; M, moving bed.
Niles-Bement-Pond Co., New York. ”

“ But actually so much is involved that subdivisions of tasks are numerous; the operations of templet-making, rolling, planing, punching and shearing, bending, welding and forging, flanging, drilling, riveting, caulking, and tubing require the labours of several groups of machine attendants, and of gangs of unskilled labourers or helpers. Some operations also have to be done at a red or white heat, others cold. To the first belong flanging and welding, to the latter generally all the other operations. Heating is necessary for the rolling of tubes of small diameter ”

“ It is a more than lamentable fact, that factions have arisen up in several states which are determined to prostrate every man who might be capable of opposing them, or dared to lisp one expression of dissent to the machinations of favouritism. ”

“ The head stock could be arranged to hold work-pieces, milling cutters or drills. Hardened tools for the necessary cutting operations could be fabricated by the machine from carbon steel in the annealed condition, then tempered, drawn, and sharpened by a separate simpler machine including a small furnace and a tool grinding wheel equipped with tool-holder and feeds. By careful standardization of parts, tools, and fixtures, it is conceivable that such a "one-machine shop" could succeed in reproducing itself. ”

“ The machine, if it cuts true once, will cut true always. Every piece of wood in a wheel ought to be shaped by machinery. The felloes should be sawn to their exact size, curve, and length by machine saws; they should be bored by machine augurs, and rounded by machine shavers. The spokes should be tenoned by machine saws, and shaped by machine lathes. The naves should be cut by a machine lathe, and the mortises in the same cut by a machine chisel. The spokes should not be driven in by the irregular strokes of a mallet, but be forced into their places by the regular pressure of a machine. ”

“ There are hundreds of drill press hands who cannot operate a milling machine, lathe hands who know nothing of planer work, and so on. The subdivision of these occupations follows closely the advance in invention, so that employers advertising for help frequently specify not only the machine tool to be used but add the name of the firm which manufactures that particular type of machine, with the result that there are about as many kinds of machinists as there are manufacturers of machine tools. ”

“ An old description of the plant says that it consisted of
an iron foundry, mould-maker’s shop, steam engine manufactory, blacksmith’s shop, and mill-stone manufactory, and a steam engine used for grinding materials for the use of the works, and for turning and boring heavy cast or wrought iron work. The buildings occupy one hundred and eighty-eight feet front and about thirty-five workmen are daily employed. They manufacture all cast or wrought-iron work for machinery for mills, for grinding grain or sawing timber ”

“ The specification describes the object of the invention to be the saving of manual labour, the reduction in the cost of production, and the superior character of the work executed. The tools were fixed on frames driven by machinery, some moving in a rotary direction round an upright shaft, some with the shaft horizontal like an ordinary wood-turning lathe, while in others the tools were fixed on frames sliding in stationary grooves. A wood-planing machine [5] was constructed on the principle of this invention at Woolwich Arsenal, where it still continues in efficient use. ”

“ The machine-shop training includes the operation of drill presses, grinders, lathes, cutters, punch and shear machines, shapers, forging hammers, and milling machines. The men work with different types of metals, receive practical experience in various kinds of machine-shop jobs, and learn how to maintain the equipment and tools. ”

“ 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. ”

“ In old times, before the invention and introduction of planing and shaping machines to work metals, the first and most important lesson taught to the machinist’s apprentice was the use of the hand-hammer and cold-chisel. When an outer shell was to be removed from a metal casting and its surface left in condition to be finished by file or scraper, the smoothness and regularity of that surface was essential, not only for economy in working, but accuracy of the file finish. ”

“ England and America produced the modern machine tool. In the period mentioned, England developed most of the general machine tools of the present day; the boring machine, engine lathe, planer, shaper, the steam hammer and standard taps and dies. Somewhat later, but partially coincident with this, America developed the special [5] machine tool, the drop hammer, automatic lathes, the widespread commercial use of limit gauges, and the interchangeable system of manufacture. ”

“ It is singular, that with the immense variety of tools set forth in the preceding chapter, how few, really, require the art of the workman to grind and sharpen. If we take the lathe, the drilling machine, as well as the shaper, planer, milling machine, and all power-driven tools, they are merely mechanism contrived to handle some small, and, apparently, inconsequential tool, which does the work on the material. ”

“ Following the milling machine, came the grinder, in which a revolving wheel of an abrasive material served to wear away the surface of a piece of work, and with this form of machine steels of great hardness could be finished with accuracy and a high polish. ”

“ In order to obtain the highest degree of efficiency in milling machine construction, it is necessary that the utmost care be taken in designing the different parts, selecting materials, and in the quality of workmanship in building. ”

“ The horizontal boring, drilling and milling machine is very efficient for certain classes of work because it enables all the machining operations on some parts to be completed at one setting. To illustrate, a casting which requires drilling, boring and milling at different places, can often be finished without disturbing its position on the platen after it is clamped in place. Frequently a comparatively small surface needs to be milled after a part has been bored. ”