A golf club head includes a club body having a crown opposite a sole, a toe end opposite a heel end, a back end, and a hosel. A first magnet is coupled to the club body. A second magnet selectively engages the first magnet, such that in a first configuration the first and second magnets attract, and in a second configuration the first and second magnets do not attract, wherein the second magnet is configured to rotate relative to the first magnet between the first configuration and the second configuration.

Summary A golf club face member is made by a manufacturing process, such as 3D printing, for a complex topology that is sturdy with good CT. 3D printing creates a face in which struts, a lattice-like structure, a waffle-iron pattern, or interior voids provide great strength and low mass. A golf club head has a club head body defining a heel portion and a toe portion and a hosel extending upward from the heel portion when the club head is at address. A face member is disposed between the heel portion and the toe portion such that it faces forward when the club head is at address. At least portion of the face member comprises a 3D printed material such as a 3D printed or sintered metal.

Embodiments of putter-type golf club head comprising a striking surface capable of achieving consistent ball speeds across the striking surface to account for various ball impact locations are described herein. The striking surface has at least two materials that differ in concentration away from the geometric center of the striking surface to provide this consistency. Consistent (or uniform) ball speed is achieved throughout the striking surface as the portion of the golf ball that contacts the striking surface interacts with at least two materials having a differing material characteristic.

In an aspect, a sports ball includes a core including a negative Poisson's ratio (NPR) foam material, in which the core has a Poisson's ratio of between 0 and −1, and in which the NPR foam material includes an NPR polymer foam; and a cover layer surrounding the core. In an aspect, a golf club includes an elongated shaft; a grip disposed at a first end of the elongated shaft; and a head connected to a second end of the elongated shaft, the head having a flat face configured for contact with a golf ball, in which the flat face is formed of a negative Poisson's ratio (NPR) foam material, in which the head has a Poisson's ratio of between 0 and −1, and in which the NPR foam material includes an NPR metal foam, an NPR ceramic foam, or an NPR-PPR composite foam.

A golf club having unique mass properties and all the benefits afforded therefrom.

A golf club head includes a club body and a resting face angle adjuster. The club body includes a crown opposite a sole, a toe end opposite a heel end, a back end opposite a face, and a hosel. The sole includes a sole surface. The resting face angle adjuster includes an adjustment member having a keel surface, and a recess formed in the sole such that a portion of the sole surface at least partially bounds the recess. The adjustment member is disposed in the recess and positionable between a first adjustment position and a second adjustment position. In the first adjustment position, the keel surface is at a first distance relative to the portion of the sole surface. In the second adjustment position, the keel surface is at a second distance relative to the portion of the sole surface not equal to the first distance in the direction.

A variable face thickness pattern is determined for a golf club head by setting a target value for a first constraint. Parametrization zones are defined and values set for a first parameter and a second parameter for each parametrization zone. Resultant first constraint values are evaluated from simulated impacts against the target first constraint value and the values are changed for the first and second parameters to result in a simulated face thickness pattern. In one aspect, the club head has a maximum coefficient of restitution at a first location of the striking face and a second coefficient of restitution that is no less than 98% of the maximum coefficient of restitution at a second location that is at least 7.5 mm from the first location. In another aspect, the club head has a moment of inertia, Izz, and a mass, mh, satisfying: Izz>mh*9.3 cm.sup.2.

Some embodiments include a golf club head. The golf club head includes a front body having a front body front portion with a front body front surface and having a front body rear portion, and includes a rear body having a rear body front portion, a rear body rear portion, and multiple protrusions. The golf club head is configured such that (i) when the front body front surface strikes a golf ball with a first amount of force, the front body deflects toward the rear body with a first amount of deflection, and (ii) when the front body front surface strikes the golf ball with a second amount of force less than the first amount of force, the front body deflects toward the rear body with a second amount of deflection greater than the first amount of deflection. Other embodiments of related club heads and methods are also disclosed.

A golf club head includes a club body having a crown opposite a sole, a toe end opposite a heel end, a back end, and a hosel. A first magnet is coupled to the club body. A second magnet selectively engages the first magnet, such that in a first configuration the first and second magnets attract, and in a second configuration the first and second magnets do not attract, wherein the second magnet is configured to rotate relative to the first magnet between the first configuration and the second configuration.

Embodiments of golf club heads and methods to manufacture golf club heads are generally described herein. In one example, a golf club head may include a body portion having a first body portion piece with a first port, and a second body portion piece removably coupled to the first body portion piece and having a second port. The first body portion piece may be at least partially filled with a polymer material. The golf club head may also include a mass portion having a fastening portion. The first and second ports are configured to be axially aligned. The second port is configured to receive the mass portion to close the second port, and the fastening portion of the mass portion is configured to engage the first port to fasten the second body portion piece to the first body portion piece. Other examples and embodiments may be described and claimed.