This release from the mould would also be facilitated by the shallowness of the groove, some 0.2mm deep as compared to Jaques 1.1mm. It is obvious that the low value for b is also important for mass constancy. What is apparent is that the specification is too tight for the Jaques bipartite method of manufacture without extreme care being taken in the process of manufacture, and if players were to demand specification balls it would be very costly considering that none of the brand new Jaques balls nor the two older ones passed specification for both mass and size. Bounce is dealt with in a separate report. The Barlow balls are irregularly and unevenly milled in comparison with either Jaques or Walker balls.
Several points arise here.
Firstly the balls need more accurate milling from the point of depth and evenness. Secondly, the number of grooves varied from a low of 68 to a high of 87 between balls, as compared with the exact 100 of both Jaques and Walker. Depth averaged 0.4mm, but ranged from 0.2 to 0.5mm. Thirdly, the slight overmass of the Barlow balls could be adequately reduced to the specified limits with the milling of angled, more frequent grooves. The present overmass average above maximum limit is only 8.09gm, easily removed in the improved milling envisaged.