US Patent 9849358 Golf clubs and golf club heads

Golf club heads include an exposed ball striking surface at a top-to-bottom center line of the ball striking face having a first material and a second material of different hardnesses. A top-to-bottom cross section of the exposed ball striking surface at the top-to-bottom center line of the ball striking face has a structure that includes a plurality of grooves including: (a) a first groove having a first edge made of the first material and a second edge made from the second material, and (b) a second groove having its opposing edges made of the first material.