Book Summary: “Tools for the Job: A Short History of Machine Tools” by LTC Rolt

Tools for the Job

Title: Tools for the Job: A Short History of Machine Tools
Author: LTC Rolt
Scope: 3 stars
Readability: 3 stars
My personal rating: 4 stars
See more on my book rating system.

Topic of Book

Rolt explores the history of machine tools with particular focus on the early Industrial Revolution.

My Comments

Given how important machine tools were to the Industrial Revolution, it is astounding to me that there are very few books on the subject. Holt’s book is the best, even though it was written in 1965.

Key Take-aways

  • Before any inventor can turn his idea into reality, a technician with a machine tool must be able to build it.
  • Technological innovation often forces innovation of new machine tools, and new machine tools enable innovation to occur in other types of technology.
  • The Industrial Revolution was dependent on the use of tools that existed long beforehand.
  • The invention of the steam engine created the demand for machine tools. Before the Industrial Revolution, there were big tools and precise tools. The steam engine and other industrial innovation needed big and precise tools. The result was set of major innovations in machine tools.
  • The same was true for the invention of the automobile and the airplane.

Important Quotes from Book

The most versatile of all tools is the human hand, but it is feeble and fallible. The aim of all tool-makers from first to last has been to overcome these defects by enhancing the power of the hand and reducing its fallibility. All hand tools and the simpler machine tools give enhanced power to the user, but so long as the tool is controlled by the skill of the user fallibility must remain. So the tool-makers attacked human fallibility by ‘building the skill into the tool’, a process which culminated-inevitably as it now seems to us-in the fully automatic tool, totally emancipated from the possibility of human error in the unwearying precision of its motions.

It has been the skilled craftsman and not the entrepreneur who has supplied the original dynamic in the story of machine tools.

One of the remarkable features of machine-tool history is the way the use of primitive tools has persisted in the midst of an advanced technology.

We should expect the clock-maker to be a pioneer of advanced techniques because the mechanical weight-driven clock was the first complex piece of mechanism to be evolved by man.

The first demand for clocks which could be described as commercial came from the medieval church. This demand was for clocks of a size which, as at Salisbury, a skilled blacksmith could construct. It was when the laity began to demand clocks of a size practicable for domestic use that clock-making became a specialised craft… The smaller the clock the wider the market, and so there was a great incentive to evolve new and more precise production techniques: accurately turned arbors, machine-cut gears and screw threads. This process of refinement and ‘scaling down’ began at the end of the fourteenth century and proceeded continuously thereafter until by the seventeenth century the clock-maker’s craft had progressed far beyond the general level of contemporary technology.

It  was, above all, the tireless driving power of the steam engine that called the engineer’s heavy machine tools into being. It was to build more efficient steam engines with greater facility that the first heavy machine shops were laid out, but first the engineers had to bring the steam engine to birth without such improved mechanical aids.

A machine tool is an expensive item of equipment. It represents an investment of capital which can only be justified if its capacity for greater productivity can be fully exploited. This condition cannot be met unless the flow of raw material to the machine and of the finished product away from it can be cheaply and reliably maintained by an efficient transport system.

In the light of this evident truth the reason why the development of precision production methods was for so long confined to the workshop of the horologist and instrument-maker becomes easier to understand. The miniature machines he used were generally made in his own shop and represented only a small capital investment. The stocks of raw material he required were small in bulk, while his finished products were also small in bulk but of high monetary value. Consequently contemporary transport problems touched him but lightly, if at all.

Such workshops employed wood for heavy work wherever possible not only because it was easier to work by hand or machine but because its availability minimised the transport problem. The use of iron was restricted as far as possible to small components which could be most readily transported either as raw material for the blacksmith or in the finished state.

In such an economy there was no room for the heavy metal-cutting machine tool, but then as now there was one trade to which normal commercial sanctions did not apply. This was the production of weapons of war… It is precisely because armament production has

always been so uninhibited that the industry has contributed so much to the general progress of technology.

With this machine John Wilkinson was able to produce a cylinder bore that was both truly circular and truly parallel throughout its length. It was used to bore the cylinders of the first two Watt engines to be built commercially.

The machine is designed round the cutting tool since its proportions, its feeds and speeds are necessarily determined by the tool’s cutting ability.

Matthew Boulton alone appreciated the true significance of Watt’s invention. It meant that in engineering the days of the craftsman millwright, who had reigned supreme ever since Newcomen had built his first engine in 1712, were numbered. The standards of accuracy which Watt’s engine demanded could only be met commercially by large-scale production in a factory equipped with machine tools.

The building of the new [Boulton & Watt’s] Soho Foundry was begun in the summer of 1795 and in the spring of 1796 its completion was celebrated by a luncheon for 200 guests. Celebration was justified for this was an industrial concentration of an entirely new kind, including as it did the first heavy engineering machine shop the world had ever seen.

The effect and the influence of these two historic machine shops at Soho and Holbeck was immense. They set engineers a new standard which was widely and speedily emulated. Almost overnight, it seemed, they transformed the appearance of the steam engine. From a crude construction of heavy timber and ‘black’ ironwork it became a precise and ordered assembly of well-finished metal parts. Now that the engineers of the new iron age had won such command over their materials, the way was open for extraordinarily rapid technical development in every sphere of industrial activity. It was no accident that the first commercially successful steam locomotives in the world were products of the Round Foundry where Murray had the tools for the job and the power to drive them.

Both works became schools for engineers who disseminated their methods far and wide.

The reason why the question of priority of invention is so often the subject of heated debate is that an historic invention is never wholly original. The function of an inventive genius is to fuse together hitherto disparate elements of which he may have no knowledge in one classical and enduring combination. Where man’s basic machine tool is concerned this was Henry Maudslay’s role…  all the elements of the modern lathe existed long before Maudslay’s day, but it was his genius and his exacting craftsmanship that refined, combined and ordered them in one beautiful tool whose polished precision set an example for posterity to follow.

Maudslay introduced to mechanical engineering those standards of precision which had hitherto been applied only upon a miniature scale by the scientific instrument-maker.

The ultimate standard of precision in Maudslay’s own workshops was his micrometer of 1805. Any dispute over accuracy of workmanship was referred to this instrument for judgement and it was for this reason that Maudslay christened it the ‘Lord Chancellor’. Now preserved in the Science Museum in London, this historic instrument represents the fountainhead of mechanical engineering technique as we know it.

The influence of Maudslay was therefore immense; indeed, among the hundreds of engineers who have played their parts in the story of machine-tool development he stands supreme. In the space of one lifetime mechanical engineering technique was completely revolutionised by his example. It was no coincidence that the same period saw the spectacular conquests of steam power on rails and on the sea and the complete transformation of many industries by the substitution of ingenious machines for hand methods. Such dramatic developments could never have come about had it not been for the’ behind-the-scenes’ revolution in the engineer’s workshop that was wrought by Henry Maudslay and his school.

Outside this closed circle of the machine-tool builders the effect of the introduction of the planing machine on mechanical engineering progress generally was immense, ranking only second to that of the lathe. It made possible the production of innumerable special-purpose machines, particularly in the textile trade.

The tool-maker’s cardinal maxim that precision of the work can only be achieved by

building still greater precision into the tool.

It was [Joseph] Whitworth who succeeded Maudslay as the dominant figure in the history of machine tools. Moreover, the firm which he founded became the most celebrated manufacturers of machine tools in the world… he first came to Manchester soon became the dominant figure in an industrial success story which, by 1850, had made that northern city the machine-tool-making centre of the world… his Manchester works he specialised in the production of engineering machine tools to an extent that was quite unprecedented. His venture was immensely successful. For the first time the manufacturer could obtain a machine tool of the highest quality promptly and at reasonable cost. Owing to their multifarious activities the less-specialised tool builders could not compete with him in rapid delivery or price. Consequently Whitworth built a reputation that was second to none and by 1850 his machine tools had dominated the workshops of the world.

When the great nineteenth-century tool-makers produced their machine tools and used them to create a variety of new and complex special-purpose machines such as Roberts’ self-acting spinning mule, it speedily became obvious that the old system of power transmission was totally inadequate to the demands which the new machines made upon it… [this goal] would be achieved only with the advent of the electric motor.

The process of increasing rotational speed in order to obtain greater power without increasing the size and weight of the parts required for its generation and transmission has been going on continuously throughout the whole course of the industrial revolution, from the Watt engine running at a stately 20 r.p.m. to the gas turbine running at 50,000 r.p.m. The rate of this progress is a reliable guide to the progress of technology generally, since increased rotational speeds are only made practicable by more accurate workmanship, better metals, better bearings, better lubrication and, above all, improved transmission systems.

The great British tool-makers succeeded in producing effective and reasonably accurate gear-cutting machines…  This was a circumstance of the greatest significance in the history of technology, because, until those principles had been successfully translated from the mathematician’s study to the engineer’s workshop the efficient transmission of power through gearing was not possible. The marine steam turbine and the motor car are but two examples of many major inventions the practical success of which was dependent on the engineer’s ability to produce efficient and accurate gears.

Within 60 years the European advantage had been overtaken and the [United States] took the lead. The pace was such that developments in technology, which would have taken generations to effect in Europe, were accomplished within the span of a single lifetime and consequently the work of a few pioneers could produce results that were astounding by European standards. Outstanding among the first generation of these ‘go-getting’ pioneers was Eli Whitney (1765-1825).

[At the Colt Armory] Colt and Root determined to carry the new principles of manufacture much further by eliminating even the smallest manual operation such as the removal of burrs from machined parts. To this end no less than 1,400 machines were installed, many of them designed by Root.

Like Maudslay’s famous works at Lambeth, the Colt Armoury spread its influence far and wide through the agency of the men who worked there.

These examples had little or no general effect on European production methods for 50 years or more. In America, on the other hand, the new technique was eagerly and speedily applied and extended, notably to the manufacture of clocks and watches, sewing machines, typewriters, agricultural machinery and bicycles.

There was a shortage of skilled labour and that the American manufacturer experienced a far more rapid turnover of labour than was the case in Europe.

Whereas in England the Chartists inveighed against machines for taking the bread out of the mouths of the poor, in America they were welcomed as the means whereby unskilled men could earn high wages and so save the capital which would give them at least a small stake in the growing prosperity of the new world. Because wages were directly related to the productive efficiency of machine methods, the more backward American industries were speedily compelled to adopt such methods in order to attract labour. Immigrant labour was not firmly rooted and could be drawn to the highest bidder as irresistibly as iron filings to a magnet.

The widely held European belief that the end product of the new system was necessarily cheap and of inferior quality was equally fallacious. It was not true of American firearms and it was not true of most of the first commercial products of the system.

From the end of the 1860s onwards, American machine tools, either imported or built under licence, began to appear in European machine shops in increasing numbers, but it was not until the present century that the’ American System’ was widely applied to commercial manufacture by European industrialists.

No other tool contributed more than the milling machine to the early history of the’ American System’.

So far this chapter has been concerned solely with New England because it was, naturally enough, the cradle of American engineering and machine tool making. But in a vigorous society that was expanding so rapidly both economically and territorially New England could not long retain a monopoly. The 1850s and ’60s saw the rapid industrial expansion

of Philadelphia which made that city for a time the greatest centre of engineering and tool-making in America.

When that [civil] war was over, however, the application of the American system of manufacture was greatly extended. This led to the rapid expansion of America’s machinetool industry and the application of features evolved in the New England

armouries to machines of heavier calibre. Skilled mechanics in the workshops of New England and Philadelphia began to look westwards and from 1880 onwards they began to cross the Alleghenies in increasing numbers. Settling in the state of Ohio at Cincinnati, Cleveland and Hamilton they prospered so well that they soon began to rival the older eastern tool-makers and Cincinnati ultimately ousted Philadelphia to become the machine-tool-making capital of America.

None of the precision metal-cutting tools so far developed could touch a hardened steel surface. The effect of the rapid development of technology during the nineteenth century was that this disability became ever more acutely and widely felt as the years went by and the speeds and stresses imposed on machines by their designers everywhere mounted. Precision components of hardened steel were what the designers needed but the engineers could not supply them… What was needed was a tool which would give precise dimensional accuracy and perfect finish to a component after it had been hardened and it was obvious that the only tool to do this was a grinding wheel.

Joseph Brown conceived an improved ‘Universal Grinding Machine’ in 1868,…  the result was an immense advance on anything built before and the parent of all precision grinding machines. Like Maudslay’s lathe and Brown’s universal miller, this was a definitive design, for despite many detail refinements the universal grinder of today is recognisably the same tool.

Whereas James Watt, in 1776, referred to a thin sixpence as a measure of accuracy and Joseph Clement referred in a similar context to a sheet of paper, the mechanic of the 1880s used a thousandth part of an inch as his yardstick. His son would soon be thinking in terms of a tenth of a thousandth.

Precision grinding machines also made infinitely easier the production of accurate hardened-steel cutting tools of all kinds: drills, taps, reamers and, above all, milling cutters… Many of the jobs which had previously been done on planers, shapers,

vertical lathes or boring machines were now performed with far greater speed and efficiency by the new milling machines. For example, a workpiece requiring machining on one face and four sides.

The gear-cutting machine which represents the climax of this phase of development did not appear until 1897. This was the Fellows gear shaper, one of the classic machine-tool designs.

History repeated itself. A hundred years earlier the future of Watt’s steam engine and Stephenson’s locomotive had lain in the hands of the tool-makers; now the success of the internal combustion engine, the motor car and the aeroplane depended no less on their ability to produce the tools for the job. Had they failed to do so, the motor car might have remained an inventor’s dream or, at best, a costly toy.

When the automobile engineers and the machine tool makers first put their heads together they started one of those closely interacting sequences of development that have been so marked a feature of the industrial revolution ever since the days of Thomas Newcomen. The machine tool maker’s new tools enabled the automobile designer to introduce better bearings and better gears and so to produce more efficient, refined and compact transmission systems. The machine tool maker quickly perceived that he could adopt the new bearings and gears to great advantage in, say, a lathe headstock with its built-in change-speed mechanism. The new lathe was supplied to the motor industry and so initiated another similar sequence.

The marriage between the electric motor and the machine tool was of crucial significance. It was the most important event in the machine shops since the steam engine had superseded the foot treadle or the waterwheel. More fundamental than either of these factors, however, was the improvement of the metal-cutting tools used in the machines.

It was only during the last two decades of the nineteenth century that the methods of scientific research were intensively applied under commercial sponsorship to the study of such processes as the cutting of metals. It was a novel concept and it speedily yielded spectacular results. The rapid development of machine tools over the last 70 years, along with the progress of technology generally, has been due more to the adoption of scientific methods of study than to any other single cause.

In these, as in many other valuable findings, the secret of Taylor’s success-and the reason why his experiments were so protracted-was that he truly distinguished all the variable factors involved in metal cutting by machine and then applied the golden scientific rule of only varying one factor at a time…

The moral of this destructive experiment was obvious. In order to reap the full advantages of the new tools the machines using them must be completely redesigned.

As late as 1930 the average British production machine shop was still a dense jungle of leather belts and line-shafting where a few modern tools jostled machines so antique that American engineers would have consigned them to the scrap heap years before.

First Germany, then France and finally Britain led the world in automobile design, producing magnificent motor cars by means of machine tools and methods which were archaic by American standards. Meanwhile on the other side of the Atlantic American engineers were using the most advanced machine shop techniques to produce cars of a crude simplicity quite unacceptable by European standards. The extreme manifestations of these contrasting philosophies were, of course, the ‘Silver Ghost’ Rolls Royce and the Model T Ford.

In the heart of the internal combustion engine-the cylinder and piston-the grinding machine proved vital. The internal grinding of large steam and gas engine cylinders proved relatively simple but the small, thin-walled bores of a multi-cylinder block for a car proved a far more difficult proposition… It was the American James Heald (1864-1931) who overcame this difficulty in 1905 when he produced his planetary grinding machine…

Heald’s machines were as essential to the success of the modern high-speed internal combustion engine as was Wilkinson’s boring bar to that of the steam engine.

It was, above all, the tools provided by such men as Norton and Heald that enabled Ford to put his revolutionary business theories into practice, but despite the spectacular success of his methods they were not widely emulated in Europe for a decade or more.

The next advance came from Germany and was so great that it brought about changes in machine-tool design even more radical than those that had followed the introduction of high-speed steels. This was the tungsten-carbide tool.

The most striking feature of machine-tool engineering in the twentieth century has been the rapid and widespread adoption of powered control systems-hydraulic, pneumatic, electric, electronic, either singly or in combination-on all but the simplest and smallest general-purpose tools.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s