It may be quite acceptable, for an experienced user of the measuring equipment, to abbreviate the measuring procedure on clubs whose grooves clearly lie well within the specified dimensions.
First, inspect the club face by eye, and check whether the grooves are:
a) unevenly spaced
b) of unequal width
c) unusually wide
d) unusually close together
If any of these conditions apply, then the full measurement must be carried out.
If none of these conditions apply, then the following abbreviated procedure may save some time and effort without affecting the outcome:
Ink and mark three grooves, and measure their width with the magnifier. Take the greatest of the three measured widths and add 0.002” or 0.05 mm to it. Call this W(+).
(For example, if the three widths were measured as 0.030” or 0.75 mm,
0.033” or 0.80 mm and 0.030” or 0.75 mm, then W(+) would be 0.033” or 0.85 mm).
Then measure the pitch, P, with the steel ruler as described in the full procedure.
Is W(+) less than 0.035” or 0.9 mm?
Is W(+) less than P/4?
Is P-W(+) greater than 0.075” or 1.9 mm?
If all the answers are YES (and you have carried out the initial visual check), the club is certain to meet the requirements of the full tests; and it may be deemed to conform without further testing.
If any of the answers are NO, the full measurement must be carried out.
IF YOU HAVE ANY DOUBT, CARRY OUT THE FULL MEASUREMENT