A method of customizing a golf club, wherein the method includes generating operating data representative of a user operating a mechanical device. The operating data is generated by a first sensor sized and configured to be removably positioned in a mounting port formed on the mechanical device during operation of the mechanical device. The sensor is interchangeably positionable in the mounting port with at least one mass insert, the at least one mass insert being adapted to be interchangeably positioned in the mounting to provide at least two different mass configurations. The method further includes determining a recommended configuration of the at least one mass insert specific to the user based on the operating data generated by the sensor, and transmitting information representative of the recommended mass insert.

A golf club head includes a body and an insert. The body defines a top side, a toe side, and a heel side, and includes a sole extending between the toe side and the heel side at a location on the body opposite to the top side. The body defines an internal volume defined between a ball-striking face and an internal wall. The insert is arranged within the internal volume and is formed layer by layer via an additive manufacturing process. The insert includes a lattice structure arranged between a rear surface of the ball-striking face and the internal wall. The lattice structure is in engagement with the rear surface and formed integrally with the ball-striking face and the internal wall.

A golf club head includes a body and an insert. The body defines a top side, a toe side, and a heel side, and includes a sole extending between the toe side and the heel side at a location on the body opposite to the top side. The body defines an internal volume defined between a ball-striking face and an internal wall. The insert is arranged within the internal volume and is formed layer by layer via an additive manufacturing process. The insert includes a lattice structure arranged between a rear surface of the ball-striking face and the internal wall. The lattice structure is in engagement with the rear surface and formed integrally with the ball-striking face and the internal wall.

A golf club head includes a main body and a plate member disposed on the main body. The plate member includes a plurality of carbon fiber layers which are stacked on each other and are impregnated with a thermoset carbon fiber resin containing carbon nanotubes. The carbon nanotubes are present in an amount ranging from 0.01 wt% to 5 wt%, based on the total weight of the thermoset carbon fiber resin.

An iron-type golf club head comprises a face having a striking surface, a back surface, and a face thickness defined therebetween. The back surface is provided with a cavity cavity-forming portion dented toward the striking surface. The cavity cavity-forming portion is provided with a protuberance in which the face thickness is partially increased, and which extends in the top-bottom direction of the head. In the cross section of the face perpendicular to the striking surface and parallel to the toe-heel direction, the protuberance has: a ridge at which the face thickness is largest in the protuberance; and a pair of inclined surfaces extending from the ridge toward a toe side and heel side of the cavity cavity-forming portion while decreasing the face thickness.

Embodiments of golf club heads and methods to manufacture golf club heads are generally described herein. In one example, a golf club head includes a body portion having a face portion with a front surface and a rear surface. A first protrusion is located at the rear surface and has a first receptacle. A second protrusion is located at the rear surface and has a second receptacle. A bridge structure extends between the first protrusion and the second protrusion. The bridge structure has a first end portion received in the first receptacle and a second end portion received in the second receptacle. The first protrusion and the second protrusion maintain the bridge structure in a compressed position. The bridge structure exerts a force against the face portion. Other examples and embodiments may be described and claimed.

Embodiments of golf club heads and methods to manufacture golf club heads are generally described herein. In one example, a golf club head includes a body portion having a face portion with a front surface and a rear surface. A first protrusion is located at the rear surface and has a first receptacle. A second protrusion is located at the rear surface and has a second receptacle. A bridge structure extends between the first protrusion and the second protrusion. The bridge structure has a first end portion received in the first receptacle and a second end portion received in the second receptacle. The first protrusion and the second protrusion maintain the bridge structure in a compressed position. The bridge structure exerts a force against the face portion. Other examples and embodiments may be described and claimed.

A golf club head alloy includes 7-8 wt % of aluminium, 2-3 wt % of molybdenum, 1.4-2.0 wt % of chromium, 0.5-1.1 wt % of vanadium, 0.35-1 wt % of silicon, with the balance being titanium and inevitable impurities. A method of using the golf club head alloy to produce a golf club head is also disclosed.

A golf club head alloy includes 7-8 wt % of aluminium, 2-3 wt % of molybdenum, 1.4-2.0 wt % of chromium, 0.5-1.1 wt % of vanadium, 0.35-1 wt % of silicon, with the balance being titanium and inevitable impurities. A method of using the golf club head alloy to produce a golf club head is also disclosed.

Provided is a rigidity characteristics measuring device that measures the rigidity characteristics of a golf club head. A head fixing jig holds the golf club head with a face surface facing upward. A linear bushing causes an impact rod to drop vertically toward the golf club head. The impact rod is equipped with an acceleration sensor. A computer calculates the rigidity characteristics, e.g., a CT value, of the golf club head, based on a detected value of the acceleration sensor.