North American Bowling News

The Making of a Bowling Ball

(The following document is provided, courtesy of Ebonite International, Inc.)

Ebonite International, Inc, has been building bowling balls for more than 100 years. From wood to rubber to plastic to today's complex balls, Ebonite International has been responsible for some of the most successful products in the industry. The company is recognized as an industry leader in terms of ball design, manufacturing and industry support. Their mission statement, "Building the Best Brands in Bowling," is clearly evident in everything they do and it permeates each step of the manufacturing process. The company is home to four bowling ball brands, Ebonite, Hammer, Columbia 300 and Track. Balls from these brands are typically classified in two ways, performance balls used by competitive bowlers, and balls used by social bowlers.


*Denotes details are proprietary information and cannot be revealed.

Bowling balls are made of basically two elements: the core (both inner and outer core) and the cover. The core serves two functions in the manufacturing process. First, the core is a vehicle used to make various weights in bowling balls (from 6 - 16 pounds). Second, and most importantly, the core also determines the shape of the arc the ball makes on the lane.

The cover determines where on the lane the arc is made. For example: on a lane of 60 feet in length and 40 inches in width, a given ball might arc several inches at 50 feet. The goal is to use the ball which is going to give you the best angle to reach the strike zone, or pocket area of the pins. The amount and placement of lane conditioner (oil) on the lane (which is determined by the bowling center) also may affect the ball's performance. An experienced bowler can match the right ball to the right lane condition to increase his striking opportunities. The goal is to knock down all ten pins in all ten frames for a possible total score of 300.

The Research and Development team is charged with marrying the correct cores and coverstocks for each ball. There are unlimited possible combinations, all of which produce a different end result. However, through extensive research, we have been able to determine which combinations are most effective for the greatest number of bowlers on the greatest number of lane oil conditions.

In addition to experienced scientists and ball design engineers, Ebonite International also employs computer aided ball tracking software to measure various combinations of cores and coverstocks. Using a digital video camera, BowlersMAP and DigiTrax analyze both the ball and the bowler to insure the core and cover combinations are effective. Both of these software programs are owned and exclusively used by Ebonite International when manufacturing bowling balls.

Ball evolution has been an upward progression from basic, non-complex geometries to today's carefully-crafted designs which have been developed to exploit the core's full inertial potential. Likewise, the cover (veneer) of balls used early on (i.e. rubber, polyester, urethane) was based on simple chemistry-type polymers but has evolved to complex mixtures of polymeric materials.


Raw materials arrive at the factory in bulk. These materials include various types of particles and fillers that are mixed to create the desired density. This liquid material is then poured into a specified shape mold, which hardens quickly to create the inner core shape.

Once the core is hardened, it is removed from the mold and the surface is prepared for the next step*. The core is measured to determine the principal XYZ axes, and a hole is drilled to mark this axis. During the manufacturing of performance ball cores, a locator pin is then placed into the drilled hole, and remains throughout the manufacturing process for core alignment purposes. Performance ball cores are designed in such a way that the orientation of the shape of the core will affect the way the ball rolls. These location devices embedded in the core will help pro shops determine proper placement of finger and thumb holes in the final product. This is the means to get the best performance to fit the bowler relative to the lane condition he is bowling on.

The types of cores designed for balls used by social bowlers are created through a similar, single step process for all weight ranges.


The inner core is then placed in a larger, round mold, and sealed tightly. Material composed of silica bubbles and a denser filler material is then poured into this mold around the inner core. The density of the filler, in addition to the core shape previously mentioned above, determines the final weight of the ball (between 6 - 16 pounds). The knob created by the mold where the mixture is poured in, is then shaved off the ball.


Not all balls are composed of the same coverstock material (veneer), although the basic elements are similar. Most balls used by social bowlers are made of basic polyester and polyurethane materials, with pigments added for color. Raw materials are brought in, just as with ball cores, and used in various combinations to create designated coverstocks.

More advanced balls, like those used by competitive bowlers, are composed of a specially-formulated polyurethane base material. This material consists of a mixture of urethane molecules and other proprietary ingredients that are combined to create a chemical reaction, almost immediately upon being joined together. This chemical reaction within minutes causes the ball to harden. These special ingredients that are added to urethane based material are the mechanisms that induce the performance differences between balls.

The combination of these components which make up the cover of a performance ball create microscopic pores that are designed to absorb lane oil. In essence, you can look at performance coverstocks as if they were a rigid polymeric sponge. This is important because it allows the ball to displace the oil that is on the lane, allowing the ball to see more friction/grab the lane in certain places to produce a desired ball movement (arcing sooner or later).

In addition, special effects pigments are used to create a variety of aesthetically appealing color and visual combinations.

After the coverstock has been applied to the outer core shape, cured and removed from the mold, it is then subjected to intense heat for a specified time period*. This helps the urethane polymer to complete its reaction at a faster rate. After the specified period of time, the ball is cooled for another specified period of time*, to slow the chemical reactions within the veneer.

One of the locations pins visible on the exterior of the ball is then filled with a brighter color of polymer material so that it is easily identifiable on the finished product.


Two sets of grinders reduce the size of the ball to a uniform size and shape, 27 inches in circumference. The size of the ball does not affect the weight of the ball. Balls are then sanded or polished based on the desired finished product. The outside texture of the ball has been determined by 'Research & Development' ahead of time, just as the core shape and coverstock was determined. Again, the possible combinations are unlimited. The equipment and products used to sand and polish the balls on the finish line in the plant are the same equipment and products sold by Ebonite International to pro shops, giving pro shops the ability to recreate brand new ball performance after a ball has been used by a bowler.

BowlersMAP and DigiTrax can again be used to ensure that balls have been created to R&D's original specifications.

Throughout the entire production process, elements are weighed and measured repeatedly to ensure Ebonite's self-imposed high quality standards. Products which do not meet specs are removed from the process and discarded at each stage of production. This is a method of continuous improvement, which helps to keep quality high and waste low. Each member of our team is responsible for and charged with maintaining our production standards. Most team members have been with the company for years; many have been with the company for more than 20 years. It's this work ethic and dedication to the product that is passed along the line and down to the end bowling ball consumer.

In addition to balls, Ebonite International also manufactures bags, bowling accessories, capital equipment, pro shop supplies and equipment and is an industry leader in bowler development and bowling coaching initiatives and programs.

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