Abstract: The illustrative embodiment of the present invention uses a tangible three-dimensional structure as a fiducial mark, which structure is, at least partially, tolerant of dimensional variations in the article. The illustrative embodiment uses three such tangible three-dimensional structures: (1) a portion of a tangible conical surface, (2) a portion of a tangible spheroidal surface, and (3) a portion of a tangible pyramidal surface.

Abstract: A device for determining the placement of gripping holes with respect to the pin and/or the center of gravity and/or the mass bias of a bowling ball has a meridian plane indicator, a vertical axis plane indicator and a horizontal axis plane indicator. The meridian plane indicator has a scale which determines the distance between placements of finger holes and a thumb hole for bowling balls. The vertical axis plane indicator has a scale which determines the distance from the horizontal axis plane to the location of the positive axis point. The horizontal axis plane indicator has two scales; the first determines the distance between the meridian plane and the vertical axis plane about the surface of the ball along the horizontal axis plane, the second scale determines the angular displacement of the meridian plane and the vertical axis plane.

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.

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.

Abstract: A guiding disk for accurately and quickly finding drill holes on a bowling ball, for finding hole positions for certain characteristics of pushaway on different bowling balls, and for avoiding positioning any hole above that of a weight in the bowling ball. The body of the guiding disk is a transparent domed plastic plate, having a reference hole and a plurality of radiant angular lines extending from the center of the reference hole. Among the radiant lines is a reference line provided at a location of zero degrees of radiant angle. Secondary spaced apart reference lines are also provided on the disk. With such a construction, positions of the holes to be drilled can be found very quickly.

Abstract: A template for weighting and placement of finger holes in a bowling ball has a meridian plane indicator and an angular indicator. The meridian indicator includes a scale which determines the distance between placements of finger holes and a thumb hole for bowling balls. A second scale is on the angular indicator to determine placement of a weighted center of gravity with respect to a bowling ball pin. The angular indicator is positioned with respect to the meridian plane indicator such that the meridian plane indicator forms the supplementary plane of the angle indicating member.

Abstract: Delays in fitting and drilling bowling balls are eliminated in a point of sale bowling ball fitting and drilling apparatus. A fitting apparatus (30) includes two movable finger blocks (34), (36) and a thumb aperture (38). Through the use of inserts taken from a group of inserts (150), the fitting apparatus (30) may be utilized to generate control signals to a drilling apparatus (46). A ball (204) may be positioned within the drilling apparatus (46) and insert receiving holes drilled therein in response to the information received by the drilling apparatus (46) from the fitting apparatus (30).

Abstract: A gauge for indicating the correct alignment for a thumb hole of a bowling ball having a ring with a circular abutment section having a central axis, the ring having an aperture through the opening inside the abutment section, the ring also having a circular track concentric and coaxial with the central axis and angular indicia on the ring. A fin is attached to the ring extending in a plane which includes the central axis. A thumb plate having a periphery which fits and rotates in the track, the thumb plate having a centrally located thumb aperture with a boundary having a generally flattened portion against which the top of the thumb will bear and an opposite generally rounded portion against which the bottom of the thumb will bear, the thumb plate also having an index mark to align with the angular indicia on the ring to indicate the correct angular orientation of the thumb hole to be drilled in the bowling ball.

Abstract: A system for transferring finger and thumb hole locations from a first bowling ball having finger and thumb holes to a second bowling ball which employs a transparent template marked to show the hole locations and the location of the first bowling ball positive axis point. The template is applied to the second bowling ball and that ball marked through the marks indicating the hole locations.

Abstract: An adjustable aid kit having a thumb sleeve and a pair of finger sleeves of hollow cylindrical form which are placed within the recesses of the bowling ball. Thumb and finger inserts are provided and fit coaxially within the sleeves. The thumb and finger inserts each have a reduced diameter threaded head which is received in a threaded aperture provided in the internal end wall of the sleeves to lock the inserts in the sleeves. The inserts each possess particularly shaped thumb and finger passages which, when employed by the thumb and fingers of the bowler on certain angles, cause particular force vectors to be applied to the bowling ball as the ball is released from the bowler's hand.

Abstract: An arcuate measuring device for measuring distances along a spherical body such as a bowling ball. The device includes a curved guide member including measurement marking thereon. A measurement device is slidably retained on the guide member. Removable pins are provided to permit measuring between two finger holes in a bowling ball. An aperture is provided in the measurement device to permit marking a distance on the ball.

Abstract: A method and apparatus for determining: (1) the location of a weight block in a previously undrilled bowling ball; (2) locating thumb and finger grip holes and determining a depth for each hole on a previously undrilled bowling ball such that the bowling ball conforms to the bowler's balance specifications; (3) the same as in (2) above except that the location of the thumb and finger grip holes and depth of the holes are drilled in order that the bowling ball will be dynamically balanced; (4) locating a balance hole and determining the depth of the balance hole on a previously drilled bowling ball such that the bowling ball conforms to the bowler's balance specifications; and (5) the same as in (4) except that the location of the balance hole and the depth of the balance hole are drilled in order that the bowling ball will be dynamically balanced.