Samuel Varley of Clerkenwell was a watchmaker, instrument maker, and scientist.
Born 24 Oct 1744.
Died 18 April 1822.
1817 The will of the late Lord Stanhope included this: 'To Mr. Samuel Varley, of Chevening, Kent, £1,000, and all my tools, machines, machinery, and instruments, mathematical and astronomical, chymical and mechanical, save and except such only as are bequeathed to Mr. Robert Walker. But in case the said Mr. Varley should not survive me, I give the said beforementioned £1,000 and said tool: and machinery, to Miss L. Varley, eldest daughter of said Samuel Varley ; but in case both of them should not survive, then the said £1,000, tools, and machinery, to go to Jane Varley, second daughter of the said Samuel Varley.' [1]
1825 Samuel Varley's method of cutting screws in the lathe was described by his nephew Cornelius Varley [2]. The lathe spindle was provided with several short threaded portions which provided a range of thread pitches (four are shown in the illustration). The lathe was equipped with a sliding flat bar alongside the headstock, guided to move parallel to the lathe axis. Fitted to the left hand end of the bar was a guide pin, which could be pushed into contact with the selected threaded portion. The right hand end of the sliding flat bar carried a tool holder. This held a form tool (a chasing tool) which was manually pushed against the workpiece to cut the thread. The guide pin and the toolholder were supported on the underside. Varley probably developed the method before 1800.
Samuel Varley also developed a lathe for optical turning, grinding lenses, watch-jewelling, and other purposes. Cornelius Varley added some improvements, mainly related to the belt drive arrangements, and described the lathe in 1829[3]. The toolholder was a prismatic bar carried in a swinging frame, providing accurate guidance for facing cuts. The depth of cut was set by a screw with a graduated collar.Varley also introduced taper fits for the lathe chuck and for the tool in its holder. Varley determined that the optimum taper was 4 degrees.
See Also
Sources of Information
- ↑ Military Register, 26 March 1817
- ↑ [1] Varley, Cornelius. "No. III. COPYING SCREWS BY THE LATHE." Transactions of the Society, Instituted at London, for the Encouragement of Arts, Manufactures, and Commerce, vol. 43, 1824, pp. 90–93 and Plate VJSTOR, www.jstor.org/stable/41325689. Accessed 15 Sept. 2020
- ↑ [2] Gill's Technical Repository, Volume 3 by Thomas Gill, 1829, p.307ff. & Plate VIII