In the early 1970s, people began experimenting with the hardness of the plastic balls, notably PBA member Don McCune. McCune at the time worked for Chuck Hamilton who invented the "soaker"—a plastic (usually polyester) ball he softened "in the garage" with chemical solvents such as MEK, sometimes to the point that the balls might even end up lopsided. These and balls subsequently manufactured with the resulting softer cover came under ABC scrutiny because of the increased scoring, particularly by McCune, who with his "soaker" won six PBA tournaments in 1973 and PBA Player of the Year honors. A ball hardness rule of 72 was established, based on durometer readings, which barred some of the softer balls. At some point in ball making and drilling, the ABC introduced ball balance regulations to prevent people from taking advantage. It was possible to drill the grip at a location relative to the weight block so that it would achieve some effect, such as to help the bowler make it roll earlier or hook more. In 1981 Ebonite began manufacturing the very first polyurethane cover stock bowling balls and sold the rights to AMF. Ebonite produced AMF balls at that time. Ebonite did not believe that bowlers would pay the $80.00 price this new technology would demand. That ball became the AMF Angle and this one coverstock change allowed the ball to get a better grip on the polyurethane finishes used on natural wood lane surfaces, which changed the nature of the bowling game significantly. Then in the late 1980s or early 1990s, Nu-Line (Columbia) produced the X-Caliber a reactive resin cover. Prior to about 1990, the ABC "static" ball balance regulations were adequate. The core was usually a uniform sphere centered inside the ball. Then competition among ball manufacturers motivated the production of balls designed to offer more than the "static balance" tricks. Materials and fabrication changes have since allowed the assembly of balls whose interior components have a much greater range of density, thereby offering a new ball choice that, in physics terms, involves the moment of inertia of a solid sphere. Eventually, "dynamic balance" regulations had to be adopted. In order to continue this discussion, a systematic description of ball rotation must be introduced. For various formulaic purposes, physicists divide rotation into three components, assigning portions to x, y and z axes that are mutually perpendicular. For bowling, the x-axis can be assigned to a line that is parallel to the foul line, the y-axis to the line parallel to the boards, and the z-axis to the vertical. Forward-roll is rotation about the x-axis, side-roll is rotation about the y-axis and mid-roll (or spin) is rotation about the z-axis. The pure full-roller delivery is a combination of forward- and side-roll only. Semi-rollers include spin. Spinners may have very little side roll. In a very strict physics sense, a ball may be delivered with rotation, but usually not in a roll, because that would imply complete traction. The technique of the great majority of bowlers involves a delivery that starts the ball in a skid that evolves into a roll that hooks into the pins. It has been known since before the 1960s that a "full-roller" type of delivery does not hook as well as "3/4 rollers" on oily lanes. On successive rotations, the "full roller" repeatedly contacts the lane on the same full circumferential circle, on which the oil accumulates, making it harder for the side-roll to find traction and create hooking action. The "full-roller" had been the dominant choice before the changes in lane coatings and oil. The "semi-roller" is now preferred (it may also be called "3/4 roller" or by other slang terms). With a 3/4-roller a bowler puts the ball into a rotation whose contact ring is smaller, and on successive rotations enlarges (subsequent examination of the ball often shows a flaring of the circles of oil). This is because at every spot along the circle, friction reduces the rotation, and that includes the spin component, causing rotation on a continually larger circle. This has the effect of bringing relatively dry ball surface in contact with the lane, increasing traction for both forward-roll and side-roll. It probably goes without saying why bowlers often wipe oil off the ball. Another effect of ball imbalance (either static or dynamic) is the ability to introduce gyroscopic effects on the rotation. The component of imbalance along the rotation axis provides a leverage that can change the orientation of the axis on its horizontal plane, an action physicists call precession. It is basically the same thing as a spinning toy top "going around in a circle." In the case of a rotating bowling ball, as it moves along the lane, there is only time for its total rotation axis to move along a short arc, but this is enough to reorient the total rotation so that some of the forward-roll becomes side-roll, increasing the side-roll provided in the bowler's delivery, thereby achieving more hook. It is possible to use dynamic ball balancing to achieve a stronger gyroscopic effect than static balancing alone. The advent of dynamic ball balancing meant that bowlers could achieve "ball flare" without the need for a 3/4 roller delivery, and more hook. Additionally, balls with covers that create higher friction, such as "particle" balls, provide for more traction and hook. Bowlers are embracing these choices, buying balls whose characteristics complement or enhance their deliveries. It is the opinion of many people in the bowling community that these advances in bowling ball technology have undermined bowling skill and have made it more difficult for lane maintenance personnel to lay out fair and credible conditions for participants. This is because advanced players using hi-tech balls "need" more oil to score high and might complain about the radical behavior of their balls on "dry" lanes. At the same time, less aggressive players might complain when they can not get their balls to hook. These complaints have been part of the game throughout USBC history. It has been a matter of which group prevails within the USBC—or what new technology comes along next.Bowling can be traced back to approximately 5200 B.C., when ancient Egyptians used stones for their balls. Pre-Columbian Indians also practiced bowling variants.
CompositionThe first bowling balls used in the United States were made of wood, especially oak, and lignum vitae wood. In about 1906 the first hard rubber balls were produced, such as the Brunswick"Mineralite" ball, and these remained the standard until the 1960s and 70s. These decades saw the emergence of plastic (polyester) balls.
Physics
Balance
Manufacturers of ten-pin bowling balls
The history of bowling ball
December 04, 2009
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