A method of manufacturing a golf club head with a plurality of stiffening members proximate the face, and particularly solid rods or a plate with one or more cutouts, is disclosed herein. The method includes the steps of preparing a wax of a golf club head body having at least one through-hole, a hollow interior, and at least one receiving pocket, preparing waxes of one or more stiffening members, inserting the wax of the stiffening members into the through-hole and seating its opposite end in the receiving pocket, bonding each of the stiffening members to the body with an adhesive material to form a combined wax mold, and casting a golf club head from the combined wax mold.

Disclosed herein is a golf club head that comprises a strike face. The strike face has a central region, defined by a forty millimeter by twenty millimeter rectangular area centered on a center of the strike face and elongated in a heel-to-toe direction. Within the central region, the strike face has a characteristic time (CT) of no more than 257 microseconds. Within the central region, no less than 25% of the strike face has a coefficient of restitution (COR) of at least 0.8. Within the central region, no less than 60% of the strike face has a CT of at least 235 microseconds. Within the central region, no less than 35% of the strike face has a CT of at least 240 microseconds.

Disclosed herein is a golf club head that comprises a strike face. The strike face has a central region, defined by a forty millimeter by twenty millimeter rectangular area centered on a center of the strike face and elongated in a heel-to-toe direction. Within the central region, the strike face has a characteristic time (CT) of no more than 257 microseconds. Within the central region, no less than 25% of the strike face has a coefficient of restitution (COR) of at least 0.8. Within the central region, no less than 60% of the strike face has a CT of at least 235 microseconds. Within the central region, no less than 35% of the strike face has a CT of at least 240 microseconds.

Golf clubs heads having a forward portion located at a front side of the golf club head and an aft portion located rearward of the forward portion and joined to the forward portion. The front portion incudes a forward joint section and the aft portion includes an aft joint section. The aft portion also includes an aft rib attached to an interior surface of the aft portion, the aft rib extends, from an interior surface of the aft joint section, in a direction away from the striking face. The golf club head may also include a crown the crown having an areal density of less than 1000 g/m.sup.2 and made from a structure comprising an inner layer, a middle layer in contact with the inner layer, and an outer layer in contact with the middle layer.

Disclosed herein is an iron-type golf club head that comprises a strike plate, an enclosed internal cavity, and a rear aperture formed in a rear wall. The iron-type golf club head also comprises a stiffening plug, within the internal cavity and compressed between the back surface of the strike plate and the rear wall. The stiffening plug is insertable, through a rear aperture, into the internal cavity. The iron-type golf club head further comprises a rear fascia covering the rear aperture and at least a portion of the rear wall. A characteristic time (CT) at a geometric center of the strike face is at least 250 microseconds. A maximum thickness of the strike plate, at the strike face, is less than 3.5 millimeters, inclusive. The strike plate, excluding grooves, has a minimum thickness between 1.1 millimeters and 2.2 millimeters.

A shim or badge is affixed to a golf cub body to produce a cap-back iron, giving the appearance of a hollow-body iron. In this way, the golf club can be manufactured with the performance benefits of a game improvement iron, while providing the appearance of a blade, player's iron, and/or a hollow-body iron. For example, by using a lightweight and rigid shim or badge to close a cavity opening in the golf club body, the golf club head can provide increased stiffness in the topline, while maintaining a low CG. Various shim or badge arrangements and materials can be used, and a filler material and/or damper can be included within the cavity to improve sound and feel, while minimizing loss in COR.

A shim or badge is affixed to a golf cub body to produce a cap-back iron, giving the appearance of a hollow-body iron. In this way, the golf club can be manufactured with the performance benefits of a game improvement iron, while providing the appearance of a blade, player's iron, and/or a hollow-body iron. For example, by using a lightweight and rigid shim or badge to close a cavity opening and extend into the toe portion in the golf club body, the golf club head can provide increased stiffness in the topline, while lowering CG. Various shim or badge arrangements and materials can be used, and a filler material and/or damper can be included within the cavity to improve sound and feel, while minimizing loss in COR.

Examples of golf club heads and methods to manufacture golf club heads are generally described herein. In one example, a body portion of a golf club head may include a top portion with a recess and a pocket inside the recess. A plate portion may be coupled to the body portion and may include a flat portion configured to fit inside the recess and a boss portion configured to fit inside the pocket. The boss portion may include a threaded port aligned with a through-port extending from a base portion of the pocket through to a sole portion of the body portion. A fastener may be inserted through a sole-end of the through-port and threadingly coupled to the threaded port to secure the plate portion to the body portion. Other examples may be described and claimed.

A golf club head with a hosel hole cover that helps improve the performance of the golf club head is disclosed. More specifically, the present invention relates to a golf club head having a hosel hole cover at a bottom portion of an interchangeable connection system that not only provides improved performance of the golf club head by strategically utilizing an existing opening to adjust the weighting of a golf club head, but it also improves the aerodynamics of the golf club head by eliminating undesirable recesses that could be detrimental to the aerodynamics of a golf club head.

A golf club head with a hosel hole cover that helps improve the performance of the golf club head is disclosed. More specifically, the present invention relates to a golf club head having a hosel hole cover at a bottom portion of an interchangeable connection system that not only provides improved performance of the golf club head by strategically utilizing an existing opening to adjust the weighting of a golf club head, but it also improves the aerodynamics of the golf club head by eliminating undesirable recesses that could be detrimental to the aerodynamics of a golf club head.