A plane is a woodworker’s tool, designed to smooth planks: it consists of a sharp metal edge slightly extending from a block of wood or metal, and may be blazoned a “block plane” for that reason. It was used as the badge of Jean sanz Peur, Duke of Burgundy, 1406 [Laurent Hablot, “The Use of Emblems by Philip the Bold and John the Fearless”, p.83]; the illustration is taken from that badge. The block plane is shown in profile, fesswise and with the toat (handle) to dexter by default. See also drawknife, float, shave.
Aleyn Kynyd ap Rhys bears: Per bend azure and argent, a block plane and a viol bendwise counterchanged.
Robert of Sugar Grove bears: Per pale gules and azure, a block plane Or.