The next few clauses of Appendix II, 3 state that:
| (i) For clubs other than putters the grip must be circular in crosssection, except that a continuous, straight, slightly raised rib may be incorporated along the full length of the grip, and a slightly indented spiral is permitted on a wrapped grip or a replica of one.
(ii) A putter grip may have a non-circular cross-section, provided the cross-section has no concavity, is symmetrical and remains generally similar throughout the length of the grip.
(iii) The grip may be tapered but must not have any bulge or waist. Its cross-sectional dimensions measured in any direction must not exceed 1.75 inches (44.45mm).
(iv) For clubs other than putters the axis of the grip must coincide with the axis of the shaft.
To take these each in turn:
(i) Circular Cross-section for Woods and Irons
Grips on woods and iron clubs are allowed to deviate from circular by having a slightly raised rib running along the full length of the grip (often called a “reminder rib”).
“Slightly raised” is interpreted to mean that the maximum and minimum diameters of the cross-section at any point must not differ by more than 0.040 inches (1.016mm). Whilst this measurement can be taken using a pair of callipers, due to the nature of gripping materials, the results of these measurements should be interpreted with caution in the field. An additional requirement, mainly for the benefit of manufacturers, is that the dimension of the rib width, from edge to edge, should not exceed 50% of the grip’s internal diameter.
In the case of a standard length grip (approximately 10 inches (254mm) in length), the “full length of the grip” is interpreted to mean that the rib must extend to within 3 inches (76.2mm) of the tip. This should generally be enough to cover the span of the player’s hands on the grip.
Fig 13. - View from inside the grip
Simulated leather wrapped grips moulded out of a rubber-like material with an indented spiral or other similar indentations are considered to be circular in cross-section and are permitted, as long as the fingers cannot comfortably fit in between the spirals or indentations. Similarly, features such as lines, dots or other patterned indentations, which are too small to fit even the smallest of fingers, would not of themselves render a grip non-circular in cross-section. However, any feature which is considered wide and deep enough to accommodate a finger or fingers could be ruled “moulded for the hands” and, hence, non-conforming.
As clearly stated in the Rule, a putter grip may have a non-circular crosssection, provided that, amongst other things, the cross-section remains generally similar throughout the length of the grip. In order to accommodate the popular (and somewhat traditional) "pistol-type" putter grips and also limit the amount of potential offset, the phrase “generally similar” is interpreted to mean: (i) that the butt (top) end of the grip must not involve a sharp change in slope or dramatic flare on the underside (see Figures 14(a) and (b)); (ii) that the flat front must extend to within 1 inch (25.4mm) of the top and bottom ends (see Figure 14(c)); and (iii) if the axis of the grip and the shaft do not coincide, the grip must be at least 10 inches (254mm) in length.
As with circular grips, features such as lines, dots, or other patterned indentations, which are too small to fit even the smallest of fingers, would not of themselves render a putter grip not “generally similar throughout the length of the grip” or “moulded for the hands”.
(iii) Cross-sectional Dimension
This clause is self explanatory and well illustrated in the Rule book.
(iv) Axis of the Grip
This clause merely requires that the axis of the circular grip on an iron or wood club coincides with the axis of the shaft. Therefore, you could not have a circular grip with the maximum diameter of 1.75 inches (44.45mm) which has been mounted onto the shaft off-centre or at an angle.