Multiple material golf club head with crown scarf joint

1. A method comprising the steps of:

providing a hollow golf club head body comprising a striking face, a face extension extending from an upper edge of the striking face, a bond flange extending from the face extension, a sole extending from a lower edge of the striking face, a rear flange extending away from the sole, and an upper opening;

providing a composite crown comprising a scarf region with a front edge having a first thickness, a step portion having a second thickness, and a rear region having a third thickness, the scarf region gradually increasing in thickness from the front edge to the step portion;

bonding the scarf region to the bond flange and the rear region to the rear flange to form an upper golf club head surface; and

grinding the upper golf club head surface only from a location proximate the front edge to a location proximate the step portion,

wherein the second thickness is greater than the first thickness,

wherein the second thickness is greater than the third thickness, and

wherein the step portion separates the scarf region from the rear region.

2. The method of claim 1 , wherein no portion of the rear region is subject to the grinding step.

3. The method of claim 2 , wherein the rear region constitutes a majority of an area of the crown.

4. The method of claim 1 , wherein the grinding step reduces the thickness of the step portion from the second thickness to a fourth thickness, and wherein the fourth thickness is greater than the third thickness.

5. The method of claim 4 , wherein a difference between the second thickness and the third thickness is 0.010 inch to 0.050 inch, and wherein a difference between the fourth thickness and the third thickness is 0.005 inch to 0.030 inch.

6. The method of claim 4 , wherein the scarf region has a front-to-back width of 0.250 inch to 1.250 inch.

7. The method of claim 1 , wherein the first thickness is less than 0.060 inch, wherein the second thickness is 0.025 inch to 0.110 inch, and wherein the third thickness is 0.015 inch to 0.060 inch.

8. The method of claim 1 , wherein at least a portion of the bond flange does not comprise any convex or concave curvature, and wherein the rear flange comprises a convex curvature.

9. A method comprising the steps of:

providing a golf club body comprising a striking face, a face extension extending from an upper edge of the striking face, a sole extending from a lower edge of the striking face, and a bond flange extending from the face extension;

providing a carbon composite crown comprising a front edge, a scarf region, a rear region, and a groove extending approximately parallel with the front edge and separating the scarf region from the rear region;

bonding the scarf region to the bond flange to form an upper golf club head surface; and

grinding the upper golf club head surface only from a location proximate the front edge to a location proximate the groove,

wherein no portion of the rear region is subject to the grinding step,

wherein the groove has a depth of 0.010 inch to 0.030 inch, and

wherein the scarf region has a front-to-back width of 0.250 inch to 1.250 inch.

10. The method of claim 9 , wherein at least a portion of the bond flange does not comprise any convex or concave curvature.

11. The method of claim 9 , wherein the bond flange has a maximum front-to-back width of no less than 0.100 inch and no more than 0.400 inch.

12. The method of claim 11 , wherein the bond flange has a constant width.

13. The method of claim 9 , wherein the scarf region has an approximately triangular cross-sectional shape.

14. The method of claim 9 , wherein the groove has a rounded cross-sectional shape.

15. The method of claim 9 , wherein the rear region comprises a visible weave pattern.

16. A method comprising the steps of:

casting from a metal material a hollow golf club head body comprising a striking face, a face extension extending from an upper edge of the striking face, a bond flange extending from the face extension, a sole extending from a lower edge of the striking face, a rear flange extending away from the sole at an angle of less than 90°, and an upper opening defined by the striking face, bond flange, rear flange, and sole;

providing a crown comprising a multi-axial carbon composite fabric, the crown comprising a scarf region with a front edge having a first thickness of less than 0.050 inch, a step portion having a second thickness of 0.025 inch to 0.110 inch, and a rear region having a third thickness of 0.015 inch to 0.060 inch;

applying a first adhesive layer to the bond flange and a second adhesive layer to the rear flange;

affixing the scarf region to the first adhesive layer on the bond flange and the rear region to the second adhesive layer on the rear flange to cover the upper opening and form an upper golf club head surface; and

grinding the upper golf club head surface only from a location proximate the front edge to a location proximate the step portion,

wherein the step portion separates the scarf region from the rear region,

wherein the scarf region has an approximately triangular cross-sectional shape,

wherein no portion of the rear region is subject to the grinding step, and

wherein the rear region comprises a visible weave pattern.

17. The method of claim 16 , wherein the grinding step reduces the thickness of the step portion from the second thickness to a fourth thickness of 0.020 inch to 0.090 inch.

18. The method of claim 16 , wherein the crown comprises a compression-molded composite material co-molded with the multi-axial carbon composite fabric.

19. The method of claim 16 , wherein each of the first and second adhesive layers has a thickness of no more than 0.010 inch.

20. The method of claim 16 , wherein the step portion extends in a heel-to-toe direction across at least 50% of the crown.