CHAPTER I✦

INFLUENCE OF THE EARLY TOOL BUILDERS

Well-informed persons are aware of the part which machinery in general has had on modern industrial life. But the profound influence which machine tools have had in that development is scarcely realized, even by tool builders themselves.

Three elements came into industrial life during the latter part of the eighteenth century. First, the development of modern banking and the stock company brought out the small private hoards from their hiding places, united them, and made them available for industrial undertakings operating on the scale called for by modern requirements. Second, Watt’s development of the steam engine and its application to the production of continuous rotative motion gave the requisite source of power. But neither the steam engine itself nor the machinery of production was possible until the third element, modern machine tools, supplied the means of working metals accurately and economically.

It is well to glance for a moment at the problems which were involved in building the first steam engine. Watt had been working for several years on the steam engine when the idea of the separate condenser came to him on that famous Sunday afternoon walk on the Glasgow Green, in the spring of 1765, and, to use his own words, “in the course of one or two days the invention was thus far (that is, as a pumping engine) complete in my mind.”[1] He was a skilled instrument maker and his first small model was fairly successful, but when he undertook “the practice of mechanics in great,” his skill and all the skill of those about him was incapable of boring satisfactorily a cylinder 6 inches in diameter and 2 feet long; and he had finally to resort to one which was hammered. For ten weary years he struggled to realize his plans in a full-sized engine, unable to find either the workmen or the tools which could make it a commercial success. His chief difficulty lay in keeping the piston tight. He “wrapped it around with cork, oiled rags, tow, old hats, paper, and other things, but still there were open spaces left, sufficient to let the air in and the steam out.”[2] Small wonder! for we find him complaining that in an 18-inch diameter cylinder, “at the worst place the long diameter exceeded the short by three-eighths of an inch.” When Smeaton first saw the engine he reported to the Society of Engineers that “neither the tools nor the workmen existed that could manufacture so complex a machine with sufficient precision.”[3]

[1] Smiles: “Boulton & Watt,” pp. 97, 98. London, 1904.

[2] Ibid., p. 114.

[3] Ibid., p. 186.

Smeaton himself had designed a boring machine in 1769 for the Carron Iron Works for machining cannon, an illustration of which is given in Fig. 1.[4] It consisted of a head with inserted cutters mounted on a long, light, overhung boring bar. The work was forced forward on a rude carriage, as shown. The method of supporting the cutter head, indicated in the section, shows an ingenious attempt to obtain a movable support from an inaccurate surface. One need hardly say that the work resulting was inaccurate.

[4] “Engineer,” London, March 4, 1910; p. 217. Drawn from the description given in Farey’s “Treatise on the Steam Engine.”

Fortunately, in 1774, John Wilkinson, of Bersham, hit upon the idea, which had escaped both Smeaton and Watt, of making the boring bar heavier, running it clear through the cylinder and giving it a fixed support at the outboard end as shown in Fig. 7. The superiority of this arrangement was at once manifest, and in 1776 Boulton wrote that “Mr. Wilkinson has bored us several cylinders almost without error; that of 50 inches diameter, which we have put up at Tipton, does not err the thickness of an old shilling in any part.”[5] For a number of years, Wilkinson cast and bored all the cylinders for Boulton & Watt.

[5] Farey: “Treatise on the Steam Engine,” p. 328. 1827.

The importance to Boulton & Watt of the timely aid of Wilkinson’s boring machine can hardly be overestimated. It made the steam engine a commercial success, and was probably the first metal-working tool capable of doing large, heavy work with anything like present-day accuracy.[6]

[6] Watt’s beautiful parallel motion, invented in 1785, was made necessary by the fact that there were no planers to machine a crosshead and guides. Planers were not developed until thirty years later.

We hardly realize the crudity of the tools available in the eighteenth century. In all machinery the principal members were of wood, as that could be worked by the hand tools then in use. The fastenings and smaller parts only were of metal, and consisted of castings and forgings fitted by hand. There were some lathes of the very simplest type. Most of them were “pole” lathes, operated by a cord reaching from a foot treadle, around the work itself, and up to a pole or wooden spring attached to the ceiling. The work rotated alternately forward and backward, and was caught with a hand tool each time as it came forward. Two are shown in Fig. 2, one at the back and one at the left. Only the very best forms had continuous motion from a direct drive on the live spindle, as shown at the right of the same figure. This figure is reproduced from the French Dictionnaire des Sciences, published in 1772. Such lathes were almost useless for metal cutting, as they lacked both the necessary power and a holding device strong enough and accurate enough to guide a tool. The slide-rest, while it had been invented, had not been put into practical form or come into general use. There were a few rude drilling and boring machines, but no planing machines, either for metal or wood. The tool equipment of the machinist, or “millwright,” as he was called, consisted chiefly of a hammer, chisel and file. The only measuring devices were calipers and a wooden rule, with occasional reference perhaps to “the thickness of an old shilling,” as above. Hand forging was probably as good as or better than that of today. Foundry work had come up to at least the needs of the time. But the appliances for cutting metal were little better than those of the Middle Ages.

Such was the mechanical equipment in 1775; practically what it had been for generations. By 1850 it was substantially that of today. In fact, most of this change came in one generation, from about 1800 to 1840. Since that time there have been many improvements and refinements, but the general principles remain little changed. With so wonderful a transformation in so short a time, several questions arise almost inevitably: Where did this development take place, who brought it about, and why was it so rapid?

The first question is fairly simple. 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 machine tool, the drop hammer, automatic lathes, the widespread commercial use of limit gauges, and the interchangeable system of manufacture.

In a generalization such as this, the broad lines of influence must be given the chief consideration. Some of the most valuable general tools, such as the universal miller and the grinder, and parts of the standard tools, as the apron in the lathe, are of American origin. But, with all allowances, most of the general machine tools were developed in England and spread from there throughout the world either by utilization of their design or by actual sale. On the other hand, the interchangeable system of manufacture, in a well-developed form, was in operation in England in the manufacture of ships’ blocks at Portsmouth shortly after 1800; and yet this block-making machinery had been running for two generations with little or no influence on the general manufacturing of the country, when England, in 1855, imported from America the Enfield gun machinery and adopted what they themselves styled the “American” interchangeable system of gun making.[7]

[7] See page 139.

The second question as to who brought this change about is not so simple. It is not easy to assign the credit of an invention. Mere priority of suggestion or even of experiment seems hardly sufficient. Nearly every great improvement has been invented independently by a number of men, sometimes almost simultaneously, but often in widely separated times and places. Of these, the man who made it a success is usually found to have united to the element of invention a superior mechanical skill. He is the one who first embodied the invention in such proportions and mechanical design as to make it commercially available, and from him its permanent influence spreads. The chief credit is due to him because he impressed it on the world. Some examples may illustrate this point.

Leonardo da Vinci in the fifteenth century anticipated many of the modern tools.[8] His sketches are fascinating and show a wonderful and fertile ingenuity, but, while we wonder, we smile at their proportions. Had not a later generation of mechanics arisen to re-invent and re-design these tools, mechanical engineering would still be as unknown as when he died.