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Basic research into metal cutting did not commence until approximately 70 years after the first machine tool was introduced. In 1851, early research by Cocquilhat was into the work required to machine a given volume of material by drilling. By 1870, the terms ‘chip’ and ‘swarf ’ were introduced by the Russian engineer Time, where he attempted to explain how chips were formed. In 1873, Hartig tabulated research into metal cutting in a book, which was the first authoritative work on the subject. A more practical metal cutting description was given by Tresca (1878), ustilising visio-plasticity models15 . In 1881, a presentation at the Royal Society of London by Lord Rayleigh of Mallock’s metal cutting research findings was given. Mallock’s scientific study of carefully etched specimens of the workpiece and attached chip for both ferrous and non-ferrous metals, where he observed them using a microscope (magnification: x5). Mallock correctly surmised from his investigation of his ‘models’ that the cutting process was basically one involving hearing and, that friction occurred in forming the chip, emphasizing the importance of this friction along the cutting tool’s face – between the chip and the tool. The sharpness of the cutting edge was also mentioned and the reasons for instability of the cutting process, leading to unwanted vibrations, or ‘chatter’. Moreover, Mallock employed basic lubricants in this work, noting that the application of lubrication reduced chip/tool interface friction. These general observations by Mallock mentined above, offer a surprisingly close approximation to today’s theories on the ‘mechanics of metal cutting’ , although his equations for the work done in internal shearing and chip and tool friction were incorrect, surprisingly, he was unaware of the ‘plasticity models’ by Tresca and his theory of ‘plastic heating’. To compound the metal cutting problems still further, in 1900, an unfortunate ‘step backward’ in the understanding of the metal cutting process was taken by Reuleaux. He suggested that a crack occurred ahead of the tool’s point and likened the cutting action to that of splitting wood, regrettably having popular support for some years. In 1907, a seminal paper by the now-famous American researcher Taylor, who published his 26 years of practical experience into investigation and research findings in metal cutting. Taylor, was fascinated by the application of time-and-motion studies that could be applied within the machine shop and in particular, ‘piece-work systems’16 . In order to enable the progression through optimisation of these time-and-motion studies, new cutting tool materials were employed, in particular high-speed steels (HSS). Taylor investigated the effect that tool materials and in particular, cutting conditions had, on tool life during roughing operations, in order to assist in the application of these time-and-motion studies. His principal objective was to establish empirical laws that would enable optimum cutting conditions to be attained. By establishing optimum cutting data for metal cutting operations and employing ‘piece-work systems’ at the company, Taylor was able to increase the Bethlehem Steel Company’s output by 500%. Of particular note, was the fact that the empirical law governing the cutting tool and its anticipated tool life17 is still used today, in the study of machining economics – more will be said on this topic later in Chapter 7 (Machinability and Surface Integrity).