Ancient bowling balls were made of stone due to availability and durability. The first bowling balls in the United States were made of hard wood, such as oak. Wood bowling balls gave way to hard rubber balls in the early 1900s. Rubber did not crack, chip, and warp like wood, and provided a more consistent performance. It was not until the 1960s that plastic balls were produced. Polyurethane balls in the 1980s paved the way for the modern resin urethane balls (or particle balls), which were first produced in the early 1990s. These modern materials gave experienced bowlers more control options.
There are two basic parts of a modern bowling ball—the core and the coverstock.
The Core
The core usually consists of a weight and a filler material, depending on the desired ball weight. Balls are manufactured to weigh between six and sixteen pounds. Lighter six-pound and eight-pound balls usually have a foam core. The core of heavier balls is often constructed of several molded pieces. To comply with modern American Bowling Congress (ABC) standards, the core must be solid and made of non-metallic materials.
The Coverstock
The coverstock is the “shell” that covers the core and creates the outside surface of the bowling ball. Most recreational bowling balls (including the house balls found in most bowling alleys) have a polyester coverstock. This common material has been a popular coverstock since the 1960s due to its low cost and durability. Polyester balls create low friction, which causes the ball to roll straighter down the lane. Although polyester balls are mostly used by beginning bowlers, some experienced bowlers prefer to use them under certain conditions (such as dry lanes).
Polyurethane (or urethane) coverstocks gained popularity in the 1980s. Urethane is softer than polyester, and therefore creates more friction. Higher friction makes the ball hook. The urethane surface can be sanded or polished to change its friction level, and therefore its hook potential. Urethane bowling balls perform best in dry lane conditions.
Resin urethane balls (also called particle balls or reactive resin balls) became the standard for experienced and professional bowlers in the 1990s, and remain the favorite today. Resin particles are embedded in the urethane coverstock, creating a tackier ball with an increased hook. These balls also produce an increased skid on oily lanes. Manufacturers are now adding textured particles (such as glass, rubber, or ceramic) to the resin balls to increase gripping ability. The result is a more controllable hook without compromising power.
How are Bowling Balls Made?
The design of a bowling ball is a scientific process. The weight and position of pieces in the core are carefully researched to result in varying ball weights and desired performance. After the design is complete, the core pieces are molded and assembled.
A pin hole is drilled in the core. The core is set on a pin, and is held suspended in a coverstock mold. The coverstock material is poured into the mold. After the coverstock material has set, the ball is removed from the pin and the pin hole is plugged with a resin. Balls are commonly molded slightly oversized. They are cut down on a lathe, and then sanded and polished for completion.
The heavy spot on the bowling ball is marked. A ball driller uses this mark and the pin hole plug location to help customize the performance of the ball when drilling finger holes. Numerous slight customizations are possible to create a bowling ball that enhances your style and ability.
