He has considerably improved upon the planing machine, in his “Jim Crow” machine, so called because the cutter reverses itself and works both ways, and in fact adapts itself to any position to do its work.
1872, August 2, The Building News and Engineering Journal, article “Railway Works at Longhedge”, volume 23, page 77:
The “Jim Crow” machine, which is Whitworth's patent, was new to some of the visitors. … But with a “Jim Crow” a cut is obtained both ways.
(rail transport) A tool for bending railway rails, by holding the rail with two arms and pushing a screw into the other side.
1886, The Railway Engineer, volume 7, page 207:
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.
1899, W. A. Smith, Railway Review, volume 39, page 16:
It is placed on the rail pretty much as a jim-crow is set, and as the middle roll is turned it travels along on the rail, curving the rail as it moves.
2013, Terry Pratchett, Raising Steam, Doubleday, →ISBN, pages 345–346:
Quelling his nerves, Moist grabbed a jim crow and opened the trap door on to the roof of the guard's van, to the initial amazement of the grag who had been trying to force his way in.