hindleys screw

from The Collaborative International Dictionary of English v.0.48

Hindleys screw \Hind"ley"s screw`\ (Mech.)
   A screw cut on a solid whose sides are arcs of the periphery
   of a wheel into the teeth of which the screw is intended to
   work. It is named from the person who first used the form.
   Hindoo