[1][2] Lock was born at Herschel House, Cambridge, the youngest son of John Bascombe Lock (18 March 1849 – 8 September 1921) who was bursar of Gonville and Caius College, Cambridge,[3] and Emily née Baily.
Lock was a Scholar at Charterhouse School, and in 1912 was awarded a Major Scholarship at Gonville and Caius College,[5] where he was the only b* wrangler of 1917.
[4][5] He was a member of the Anti-Aircraft Experimental Section, and in 1920 moved to the Aerodynamics Division of the National Physical Laboratory in Teddington,[5] to work on the dynamics of shells.
[5][8] He developed the pitot-traverse method for measuring profile drag, and investigated the effect of sweepback at high Mach numbers.
[5] Lock married Lilian Mary née Gillman (1886/7–7 Oct 1966, aged 79) on 26 April 1924, at St Leonard's Church, Streatham.