the defined radius roll passageway 285 or a defined distance along the slot from one of the inside roll plates 282 outward 283 the second roll pivot pin is then set in the matching locator passageway or position in the slot in the other roll plates from the inside out such that the yoke pivots freely vertically see fig2 the defined roll is ready for shaping as hereinafter described bulge is the horizontal face curvature from toe to heel and is also truly circular see fig1 c radii tr of 9 to 15 inches are typical a main function of bugle is to compensate for a swing which marginally fails to bring the sweet spot into contact with the ball inherently a difficult maneuver thereby eliminating a minor tendency to slice or hook and to increase in combination with roll the transfer of maximum power from face to ball the defined bulge radius tr is selected by insertion of the bulge pivot pin 296 in the defined radius passage 295 or a defined distance along the bulge radius slot disposed on the upper bulge swivel keeper 291 through its matching passageway in the swivel plate 290 and through a similar passageway in the lower bulge swivel keeper 292 to establish the bulge radius 297 the face is then shaped as hereinafter described see fig1 b face progresssion r is the horizontal distance between.