David Wilkinson

David Wilkinson (1771-1852) US Engineer and inventor.

1771 Born at Slatersville (Smithfield), Rhode Island, the son of Oziel Wilkinson (1744-1815). Oziel was a skilled blacksmith and in 1783 established works for making farm tools and domestic utensils at Pawtucket. The business expanded with the help of his sons, and by 1800 it was regarded as the leading iron and machinery making business in New England. In about 1800 David and his brother Daniel established a company called David Wilkinson & Co. The firm collapsed in 1829. David established a new business in Cohoes, NY, but this was not a success, and from 1836 he travelled to undertake civil engineering work. In 1848 he successfully petitioned Congress for a reward for the invention of his screwcutting lathe, and was awarded $10,000. He died in Caledonia Springs, Ontario, Canada, on 3 February 1852.

'..... He was early initiated into all the mysteries of the blacksmith's trade, and when his father moved to Pawtucket Falls, when he was not far from thirteen years of age, he was quite an expert in wielding the sledge." He was the inventor, when but a young man, of what is known as the "sliding lathe," for turning iron and brass. Then he invented the "slide or gauge lathe," and after a good deal of opposition and discouragement succeeded in getting a patent for it. For several years he reaped little or no pecuniary benefit from his patent, which in twelve years ran out, and he neglected to renew it. In consideration of the great utility of his invention, especially in the arsenals and armories of the United States, Congress voted him, in 1848, the sum of $10,000.

'It is claimed, moreover, for David Wilkinson, that he was the first person in this country to make use of steam for propelling boats, anticipating the experiment of Robert Fulton on the Hudson River about sixteen years. The boat used by Wilkinson was one belonging to one of the large India ships of John Brown, and was about twelve tons burden. A mechanic by the name of Ormsbee prepared the boiler, and Wilkinson built the engine. The work of getting the boat into running order was done at a place about three miles and a half from Providence, called "Winsor's Cove," a quiet spot, where the parties interested would not be liable to be molested by the over-curious. The story goes that Wilkinson succeeded in getting his machinery in operation, and on a pleasant evening in autumn he left Winsor's Cove in the first boat propelled by steam that ever floated on the waters of the Narragansett Bay and Providence River, and arrived in safety at the lower wharf. The next day they left, in the boat, for Pawtucket, to show the friends in that village the success that had attended the enterprise. At Pawtucket the boat remained a day or two, and then returned to Providence. For some reason unknown to us no practical benefit accrued to Mr. Wilkinson from his invention.

'In 1829 he moved to Cohoes Falls, in New York, where he engaged in manufacturing business, and subsequently, when manufacturing was no longer profitable, was occupied in various enterprises where his mechanical skill was brought into requisition. He died at Caledonia Springs, Canada West, February 3, 1852, and his remains were brought to Pawtucket and placed in the family vault.'.

Wilkinson is often cited in the USA as the inventor of the 'slide lathe' in the 1790s. Slide lathes, where the cutting tool is guided by slides built into the lathe, were already in limited use in Europe by this time, although their existence would not have been widely known, and they were probably not offered for sale. Given the apparent importance and widespread use of the lathe for which Wilkinson was awarded $10,000 in 1848, there is a surprising lack of information about it, unless it was the screwcutting machine referred to below. More likely, the award may have been made for another machine, a lighter and more versatile 'guage or sliding lathe', said to have been completed by Wilkinson in 1806, but not patented. In fact it is difficult to see what features of an early lathe could be regarded as patentable. Slide lathes were certainly in fairly widespread industrial use in Britain by 1806.

Screwcutting Machine

Wilkinson patented a screwcutting machine on December 14th, 1798. The original patent documents were destroyed in a fire in 1836. The specification was redrawn some time after the fire (on what basis the replacement drawings were derived is not known), and the drawings are available online.

The patent drawings show a form of lathe having a master leadscrew geared to a central spindle. The same spindle pinion drove another gear to rotate the workpiece. The master leadscrew acted to traverse a carriage running on three wheels, its sides constrained by guides. The carriage carried a toolholder, and the tool's depth of cut in the workpiece was adjusted by a screw. However, as drawn, the screw could only be used to push the tool inwards, after releasing the clamping screw. Therefore it could not be used to carefully feed the tool in to establish the depth of cut. This was similar to the arrangement used on Senot's Lathe of 1795.

It is evident that the action of the leadscrew on the carriage and the opposing action of the tool would tend to twist (rotate) the carriage (as viewed from above), and the arrangement of the wheels and side rails appears to be ill-suited to resist this tendency.

There is no provision for adjusting the tool's axial position relative to the workpiece.

The leadscrew follower was split vertically, taking the form of spring-loaded jaws. The jaws were held closed by a swinging latch, and the follower was disengaged automatically by the latch striking a trigger near the tailstock.

Having completed the first of a series of incremental cuts, it would presumably be necessary to withdraw the cutting tool and then push the carriage back manually to start the next cut. The leadscrew follower would then be closed and latched manually to start the next cut.

Curiously, the drawing shows each 'headstock' having only a single bearing.

The machine is shown with its central spindle being directly driven by a small waterwheel. No means of disengagement from this power source is shown, a prospect likely to alarm anyone familiar with screwcutting in a lathe!

A question arises over the effect of iron chips (swarf) accumulating in the path of of the carriage rollers as machining progressed.

As drawn, the machine would only be capable of cutting screws of the same pitch as the master leadscrew. Clearly it was by no means a versatile machine tool. In the absence of change wheels, a different leadscrew would have to be fitted to cut threads of a different pitch. There is no provision for turning the forged workpiece down to the required outside diameter before threading.

The novelty of the machine appears to lie in the provision of split nut which could automatically disengage the leadscrew from the carriage, and in the use of wheels for the carriage. The principle of using a master leadscrew geared to the workpiece via an intermediate gear was already established and in the public domain. One maker was Jesse Ramsden, whose detailed description of a small screwcutting machine was included in his Paper describing his dividing engines, published in 1777. Initially available to anyone who could afford the 5 shillings cost, it was later reproduced in many encyclopedias.

An interesting statement regarding the machine may be found in 'Early Engineering Reminiscences (1815-40) of George Escol Sellers':-

'... the patent drawing of the 1798 screwcutting lathe of David Wilkinson, of Providence, is a restoration, made after the Patent Office fire of 1836, and in view of Wilkinson's later attempts to obtain compensation from Congress for inventing a machine (the lathe) that was then in wide use in the government arsenals, the detailed resemblance of the restored drawing to the original machine is open to question.'

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