A Guide to the Rules on Clubs and Balls

Putter Face

The specifications in Appendix II, 5, with regard to roughness, material and markings in the impact area, do not apply to putters. However, any grooves or other permissable markings on a putter face must not have sharp edges or raised lips.
In addition, if a groove or the grooves on the face of a putter exceed 0.035 inches (0.9mm) in width and 0.020 inches (0.508mm) in depth, the following guidelines apply:
• The width may not exceed 0.060 inches (1.524mm);
• The width to spacing ratio must be no less than 1:1; and
• The depth must be less than the width, and may not exceed 0.040 inches (1.016mm).