Henry Maudslay: Machine Tools
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Note: This is a sub-section of Henry Maudslay.
Henry Maudslay was the most influential machine tool maker at the end of the 18th and start of the 19th centuries.
It is intended in this section to identify as many of his machine tools as possible. He became famous for making the blockmaking machinery at Portsmouth, and for his lathes, which spearheaded the industrial application of slide lathes and machine screwcutting. See Portsmouth Block Mills for more information on the blockmaking machinery.
His first known machine tools were produced for lockmaking, during his employment with Joseph Bramah from 1790 to 1797.
Maudslay's Lambeth workshop became a 'nursery' for many men who would become famous engineers in their own right, and who would advance machine tool technology to its next phase, with machines of heavier construction and greater versatility.
Maudslay's best-known lathes featured triangular bar beds. The earliest known example of a lathe with a triangular bar bed was made by Henry Hindley before 1758, and early lathes of somewhat similar design by other makers are not uncommon. Very few by Maudslay are known to exist. Maudslay's have certain distinctive design features, and display fine workmanship.
Examples of Maudslay lathes can be seen in a number of museums. The London Science Museum has on display an early screwcutting lathe. Some historians put the date at c.1797-8. Maudslay left Joseph Bramah's employment and set up on his own in 1797, and it is likely that he would have devoted early attention to screwcutting developments. Also, his reputation as a machine tool maker was well-established by 1800, when Marc Brunel sought him out to build models of his blockmaking machines for Portsmouth Block Mills. This 'pre-1800' lathe was powered by hand, and generations of apprentices were required to produce screws on it. This is said to explain why it is 'opposite handed', with the headstock on the operator's right hand side: presumably most apprentices came, and left, with stronger right arms.[1] The model screwcutting lathe is similarly handed and hand-powered.
The Science Museum has on display a model of a hand-powered screwcutting lathe (see photos). It represents an advance on the 'pre-1800' lathe in a number of respects.
The Science Museum's complete Maudslay treadle lathe is currently not on display. Photo here and here.
This c.1805 example in Australia, originally owned by Sir John Barton, is ascribed to Maudslay, Sons & Field. However, while the slide rest is fully consistent with Maudslay's design and construction, some other keys aspects, primarily the headstock and tailstock, are not Maudslay-like.
The Henry Ford Museum in the USA has two examples. One is a treadle lathe similar to that in the Science Museum's collection, but with the addition of a form of 'back gear' - an important development. The other lathe ascribed to Maudslay is larger. Like the smaller well-known screwcutting lathe in the Science Museum, it has a two-bar bed and a central leadscrew, and has a close family resemblance to that lathe, particularly in the detail of the carriage and the toolholders. Unusually, though, the carriage is held down by rollers pressing on the underside of the slideways. Another unusual feature shared with the Science Museum lathe is that it is 'opposite handed', i.e. the headstock is to the right of operator, contrary to later universal practice. This lathe was gifted to the Ford Museum by Sir W. G. Armstrong, Whitworth and Co. Photographs here.
1806 Some machines were observed at Maudslay's works in Margaret Street, Cavendish Square, and described in Olinthus Gregory 's Treatise of Mechanics, published in 1806[2]. Drawings were produced by John Farey and may be seen here . One of the machines described was a treadle lathe with four-speed pulleys. The large lathes in the works were turned by men cranking large wheels. A strap from the large wheel turned pulleys fixed to the ceiling, from which the lathe was driven by a catgut belt. The ceiling pulleys were mounted in a weighted frame which maintained belt tension. The operator had control of the drive by fast and loose pulleys, rather than stopping the men turning the great wheel. The text also describes how gears were cut using the large lathes. The workpiece was held in the chuck or on the faceplate, and the angular positions set using the index holes in the largest pulley (17 concentric circles of holes). The rotating cutter had four teeth and its spindle was held in a frame held by the toolholders on the compound slide. The power was taken from the great wheel, and speed was stepped up by pulleys to a remarkable 7300 rpm. The spindle was set loose in its conical bearings such that it when it expanded it would would have a satisfactory running fit. The cutter spindle could be angled for cutting wormwheels. The text includes a non-too lucid description, and a drawing which looks like the work of M. C. Escher, of an arrangement involving oblique slots which appears to serve to adjust the height of the compound slide.
Advertisements
1825 A 'good second-hand Turning Lathe, by Maudsley' was advertised for sale, along with a braiding machine,at 44 Chandos Street, Covent Garden[3]
1832 Advert: 'TURNING LATHE.- To be SOLD, a Gentleman's TURNING LATHE, made by Mr. Maudsley, London, at the Cost of £220; to be Sold for £100. Particulars may be known on Application to Mr. Donkin, Land Agent, Bootham, York, or by Letter, Post-paid.'[4]
Screwcutting
Maudslay devoted considerable time and effort to the production of increasingly accurate screws. At one end of the scale they would be used for interchangeable fasteners, while at the higher end they would be leadscrews for machine tools, and, in their most accurate form, for measuring instruments, scientific instruments, dividing engines, etc.
He adopted various methods to generate screw threads. One way is frequently described in histories of engineering in terms which convey the impression of a primitive method. In fact nothing could be further from the truth. Even the noted machine tool historian K. R. Gilbert might have inadvertently conveyed this impression, when writing: 'In the method finally adopted a hard-wood cylinder was rotated in a suitable holder against a crescent shaped knife held obliquely to its axis. The knife in cutting into the cylinder caused it to traverse, thus generating a screw which could be copied in steel.'[5] In fact Maudslay produced a very sophisticated device to accurately guide the wooden or soft metal cylinder. The device is on display in the Science Museum, and the quality and sophistication will be apparent from the first two photographs above.
Machines Photographed Following Closure of Lambeth Works in 1900
Staff from 'Engineering' magazine visited the works when its contents were about to be sold off, and reported on their findings[6]. Many of the machine tool photographs are reproduced here. Their inclusion does not necessarily imply that Henry Maudslay was involved in their design, although all the machines illustrated do have some Maudslayian features.
A characteristic of Maudslay's designs was the elegance of their details, with well-shaped, slender castings and forgings, all made with an insistence on very high standards of fit and finish. Massive construction was not a hallmark, though, and his typical structures obtained their stiffness using slender ligaments and extensive cross bracing. This concept was not followed by his successors, who moved towards a more rational approach, with weight not being seen as such an adversary. The likes of Fox, Roberts, and Whitworth would adopt box-like bed castings, but we must also recognise that Maudslay did use shallow box beds with dovetail slides on some of his machines, namely the model screwcutting lathe in the Science Museum and the Portsmouth pin-turning lathes and facing lathes.
The typical frame castings, with their classical columns and slender bracing, may well reflect Marc Brunel's input to the Portsmouth blockmaking machinery designs.
The shaping machine is unimpressive. It appears that the coarse setting of the cutter height demands the adjustment of the nuts on four threaded columns. The bedplate supports clearly point to Henry Maudslay's era. It is a pity that we do not have a photograph of the other side, to see whether the machine had automatic traverse. According to J. G. Moon, the stroke could be adjusted by moving the crankpin in a slot.[7] It was able to cut in both directions, using a rotating tool holder later revived by Joseph Whitworth. A point of interest is that James Nasmyth claimed to have invented the shaping machine or 'steam arm' in 1836. Maudslay's machine surely predated this. As W. Steeds points out, it is unlikely that Maudslay's works would have built their machine if something much better had been available from Nasmyth at the time.
Another interesting machine, with many typical Maudslay characteristics, is the boring and facing machine. In one mode it could be used with a boring bar supported by the tailstock. Aleration of the centre height required the work piece to be raised on packers, or for the auxiliary table to be raised on its jacking screws. The machine could also undertake facing (the article called it milling, but flycutting might have been more likely). The headstock could be traversed manually or automatically.
The bevel gear cutting machines may well be out of place here. One has what may be a recycled bed, while the other, for larger diameter gears, has a more modern-looking box frame. In fact the only typical Maudslay influences are in the design of the pulleys on the latter machine.
See Also
Sources of Information
- ↑ 'English & American Tool Builders' by Joseph Wickham Roe, 1916, quoting the recollections of James George Moon
- ↑ [1]
- ↑ Morning Advertiser - Monday 19 September 1825
- ↑ Leeds Intelligencer - Thursday 23 February 1832
- ↑ 'A History of Technology': Vol IV, Oxford University Press, 1958
- ↑ 'Engineering' 18 January 1901
- ↑ 'English & American Tool Builders' by Joseph Wickham Roe, 1916, quoting the recollections of J. G. Moon