Method for machining a groove in a metal surface

A method of providing an essentially planar face of a metal object with a groove which extends between selected margins of said face without intersecting said margins, said groove being uniformly curved on an arc of radius "r" and being of a width "w" and a constant depth "d",said method comprising:

• providing a broach which is uniformly curved from a leading end to a trailing end on an arc of radius "r", said broach having a base with a planar surface of width greater than "w", and a series of fixed cutting teeth of width "w" perpendicular to said surface, the teeth of said series being progressively longer from said leading end toward said trailing end and the last tooth in said series being of a length no less than "d";
• positioning said article so that its planar face is perpendicular to an axis and the line of the groove to be cut is on an arc of a circle of radius "r" struck about said axis;
• positioning said broach so that it occupies an arc of said circle in a plane parallel to said face and with the leading end portion of the planar surface of the broach base confronting said face;
• producing relative motion of the object and the broach about said axis with said surface moving in a plane parallel to said face, so as to cause said series of teeth to cut said face of the object progressively;
• continuing said motion until all of said teeth have traversed the entire object to form a continuous groove which intersects both of said selected margins;
• and plugging the end portions of the groove to effectively obliterate said groove for predetermined distances inwardly from said selected margins.