Lay out axis through light and heavy centers of bowling balls.
What does a Bowling Ball Grader and Marker do?
Lays out axis through light and heavy centers of bowling balls and gauges and grades balls according to size, color, and quality: Floats bowling ball in mercury pool and locates and marks center of light side, using plumb bob and grease pencil. Places ball in jig and locates center of heavy side, using center gauge. Examines ball for defects and color quality, measures size with ring gauge, and marks data to be engraved under trademark, using grease pencil. Places rejected balls aside for reworking.