jimcro

Noun

Jim Crow

1. (historical) A World War II code name for patrols along the British coastline to intercept enemy aircraft, originally intended to warn of an invasion in 1940.
   • … flying cannon equipped Spitfires V’s mainly on ‘Jim Crow’ operations (operational Patrols along the home coastline intercepting any hostile aircraft and looking out for any invasion forces).2008, Simon Muggleton, The Battle of Britain Monument in London
2. A double-action planing tool invented by Joseph Whitworth, in which the blade ‘jumps’ to face the other way on the back-stroke.
   • Two other machines exhibited by Whitworth… One was furnished with a reversing tool to plane both ways, and called, from its peculiar motion, a Jim Crow machine.1852, Charles Tomlinson (editor), Cyclopædia of Useful Arts, Mechanical and Chemical, Manufactures, Mining, and Engineering, volume 1, section xiv “Machinery Exhibited”, page cxliii
3. A tool for bending railway rails, by holding the rail with two arms and pushing a screw into the other side.
   • When rails have to be bent with a Jim Crow, as in setting stock or check-rails, or straightening a bent rail, they should always be heated first, or they are liable to crack, especially steel rails.1886, The Railway Engineer, volume 7, page 207

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