Abstract: A device for locating bowling ball gripping apertures with respect to a bowling ball weight block angle inherent to that particular bowling ball and the track of a particular bowler. One embodiment of the device includes a curved base portion adapted to substantially rest on a curved surface of a bowling ball, the perimeter of the base portion including degree indicators and the center of the base portion including a hole, at least four curved angle indicator arms adapted to substantially rest on a curved surface of the bowling ball, the angle indicator arms including length measurement indicators, the angle indicator arms connected with and extending from the curved base portion, and at least two of the angle indicator arms are adapted to rotate about the center of the curved base portion.