Early Milling Machines

The Wikipedia entry for Milling (machining) is recommended as a good source on the history of the development of milling machines. There is no point in duplicating the information presented, so this entry will be limited to some lesser-known aspects of the milling of metals.

A milling process had been in use from the 17th century to machine gears for clocks and watches.

It is likely that milling, or at least flycutting, would have been undertaken on ordinary lathes prior to the introduction of purpose-built milling machines.

The earliest milling machines made in the USA in the early 19thC were very similar to lathes, with the workpiece being movable in the X and Y planes. Various claims have been made about 'interchangeable manufacture' and the associated use of milling machines in the second decade of the 19th century. However, successful milling of iron to produce accurate work with a satisfactory finish makes considerable demands on the rigidity of the machines and on the quality of the cutters, and would seem surprising if the challenges had been addressed and overcome at that time. It is perhaps more likely that milling was used for roughing out, using semi-skilled labour, leaving the finishing to be done by filing.

An early example of a milling machine with third axis (vertical) movement was that introduced by Gay, Silver and Co in the USA c.1841. It also featured overarm support for the spindle.

Another early type of milling machine with Y-axis movement came to be known as the 'Lincoln Miller'. It resembled a lathe, but with a simple arrangement for elevating the spindle by raising each of the two headstock bearings by screws. Various names have been associated with its development: Thomas Warner, Frederick W. Howe, Elisha Root, and Francis A. Pratt.. The first examples were made at the Phoenix Iron Works, Hartford of George S. Lincoln and Co in the early to mid 1850s.. The arrangement for elevating the bearings was inconvenient, and it seems likely to impair the rigidity of the machine, and hence its acccuracy, productivity, and and ability to produce a good finish. Nevertheless, Lincoln millers were produced in vast numbers and remained in production for decades. On some, an outboard bearing was added, corresponding to the tailstock of a lathe.

The next type of milling machine from the Phoenix Iron Works was the Lincoln Index milling machine, also designed by Pratt and built by Whitney. The spindle bearings were fixed in the headstock (i.e. non-elevating). The headstock could be moved relative to the workpiece in the X and Y planes. The workpiece was held in a vice or other fixture on top of a vertical cylindrical column which could be elevated (Y plane movement). The column could also be rotated, and was supplied with an indexing (division) plate. Starting in 1861, numerous examples were supplied to the armoury of Samuel Colt.

Some British Developments

James Nasmyth wrote about a machine he built c.1830, while working for Henry Maudslay, to mill the faces of small hexagon nuts. He developed self-acting industrial versions of the machine and was selling them in the late by 1837. Writing to a customer in 1838, he advised that the cutter should never exceed 55 rpm to avoid damaging the cutter. By 1839 Nasmyth, Gaskell and Co had sold over 50 machines.

Richard Roberts produced self-acting machines on a commercial basis to machine hexagonal and other multi-faceted components, and these were sometimes described as 'polygon machines'. They were made by firms in which Roberts was involved, namely Sharp, Roberts and Co (early 1840s), Sharp Brothers and Co (early 1850s): see Directory of Manchester and Salford, 1853. p33-37, Roberts and Dobinson (early 1850s).

Kendall and Gent made a nut and bolt head cutting machine with three milling heads, allowing rapid production using cheap labout.

Richard Roberts was undertaking milling on a larger scale by 1839, when American visitor William C. Davol described Roberts's ' Cutting Engine for cutting locomotive Engine cranks, the cutter was made by having a cast Iron wheel about 18 inches in Diameter 3 1/2 to 4 In wide with cavitys cut in the edge about 3 In deep to 5/8 wide set 3 In apart round the face of the wheel to receive the steel cutters which was ruther wider than the wheel and ground sharp on three sides. '

A number of British firms produced machines for cutting keyways and slots for cotters using rotating cutters. These were commonly called slot drilling machines. Nasmyth, Gaskell and Co started making such machines c.1853, calling them 'patent grooving machines', although they were not patented by Nasmyth. Sharp, Stewart and Co started making such machines in the mid 1850s to Sharp and Furnival's patent of 1855. An accurate large scale model from c.1857 is/was on display at the Musee des Arts et Metiers in Paris. The Science Museum have a sample workpiece produced on one of these machines. Photo here.

These slot drilling machines were effectively vertical milling machines, but their makers did not develop these or other milling machines to increase their versatility, unlike the situation in the USA, where universal milling machines were developed and revolutionised aspects of engineering production. The most prominent early universal machines came from Brown and Sharpe of Providence, RI. In addition to machining flat surfaces, grooves, etc., they were available with accessories to allow the machining of gears, twist drills, splines, etc.

Note: The Marc Brunel/Henry Maudslay blockmaking machinery at Portsmouth included a form of vertical milling machine built in 1803. However, it machined lignum vitae rather than metal. Also, it was by no means a versatile machine, having only one purpose, namely the milling of recesses in the sheaves.

See Also

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