Golf club heads and methods to manufacture golf club heads

A golf club head comprising:

• a body portion;
• and
• a face portion coupled to the body portion, the face portion comprising:
• a front side,
• a back side opposite the front side,
• a perimeter edge having a face toe edge, a face heel edge, a face top edge, and a face sole edge,
• a perimeter portion on the back side extending inward from the perimeter edge, and
• a recessed portion on the back side at least partially surrounded by the perimeter portion, the recessed portion having a minimum thickness portion and a maximum thickness portion located between the face toe edge and a vertical plane bisecting the face portion,
• wherein the face portion has a thickness transitioning from the maximum thickness portion toward the perimeter edge according to a first gradient slope in a direction toward the face top edge and a second gradient slope in a direction toward the face heel edge, and
• wherein the magnitude of the first gradient slope is greater than the magnitude of the second gradient slope.

A golf club head comprising:

• a body portion;
• and
• a face portion coupled to the body portion, the face portion comprising:
• a front side,
• a back side opposite the front side,
• a perimeter edge having a face toe edge, a face heel edge, a face top edge, and a face sole edge,
• a perimeter portion on the back side extending inward from the perimeter edge, the perimeter portion having a perimeter portion width that varies around the perimeter edge and a center-heel perimeter portion located proximate to the face heel edge, and
• a recessed portion on the back side at least partially surrounded by the perimeter portion,
• wherein the center-heel perimeter portion has a maximum heel perimeter portion width greater than a perimeter portion width of portions of the perimeter portion adjacent to the center-heel perimeter portion in a top-to-sole direction.