How to Determine whether Clubs Available Prior to 1 January 2010 Conform to Pre-2010 Groove Requirements(applicable to golf played where the Groove and Punch MarkCondition is not in use)

(i) Groove Width

If the average width of the measured groove widths exceed 0.035” (0.889 mm) then the club is non-conforming.

If any single measured groove width exceeds 0.039” (1.0 mm) then the club is non-conforming.

(ii) Groove Separation

The pitch of the grooves, as described in Section 8, must not be less than four times the width. Thus, the grooves do not conform if P/AWav is less than 4.0.

P – AWav must not be less than 0.075” or 1.9 mm.

(iii) Groove Consistency

The difference in width between the second widest and the second narrowest groove must not exceed 0.004” or 0.1 mm. The grooves do not conform if AWvar is greater than 0.004” or 0.1 mm.

11. It is recognized that groove measurements made, as these are, at one point along the length of the grooves, are sensitive to small manufacturing errors. Therefore, if a club fails on one of the above criteria, it should not immediately be declared non-conforming; but the whole measuring procedure should be repeated at a slightly different part of the face (say 0.394” or 10 mm to the other side of the centre of a club face from the first set). For a club to be declared nonconforming, it must fail to meet the same specification on both sets of measurements. In the case of a single overwidth groove (AWmax), the same groove must be overwidth on both measurements.