They’re hard, they’re round, and they’re heavy. Bowling balls roll across lanes to hit the most number of pins. But ever wonder how they’re made? The history of bowling balls and the sport can be traced all the way back to ancient Egypt when archaeologists dug up what appeared to be stone pins.
It also had its time during the middle ages and got so popular during the 14th century that King Edward III had to ban the sport so his army could focus on other types of activities (i.e. archery and sword fighting).
The Evolution from Wood to Complex Material Combinations
The earliest bowling balls were made of hardwood taken from a slow-growing tree that produces paired oranges. This type of wood is called lignum vitae and is heavy enough to sink in water. It was only in the beginning of the 20th century that rubber bowling balls became commercially available and mass-produced.
It would take another 70 years before the two most famous brands of rubber balls would be replaced. Evertrue and Mineralite would be replaced with newer, synthetic materials. Urethane and other polyester materials would be used for the coverstock. Innovations in core design would come later.
Core, Weight, and “Reactive” Balls
Long time players of bowling alleys such as Bowlero and Dave & Busters would notice that the lanes have different textures, and so, would affect how the ball travels. That’s why most bowling balls today have different types of coverstock and core shapes to affect how it rolls on the lane. The coverstock’s material gives the ball the necessary smoothness while the core provides a bonus on the spin.
The type of cores and coverstocks used have so much contribution to the sport that the ABC (American Bowling Congress) recorded an increase in the number of perfect strikes during its first winter season.
Reactive balls are a combination of the creative use of materials for the coverstock and the unique core shapes. There’s currently three general categories of coverstock: solid, pearl reactive, and hybrid reactive. Solid coverstocks have a less smoother surface area so it hydroplanes over oily surfaces.
A pearl reactive coverstock on a bowling ball would mean a higher density of micropores in the surface area. This will allow it to have less skidding and more hitting power upon reaching the pins.
Hybrid reactive balls combine the hooking strength and hydroplaning ability of both solid and pearl reactive balls.
Step-by-step Construction of Bowling Balls
The very first step in constructing bowling balls would be choosing the core material and design. The molds are pre-formed for a cast. The mold and cast are designed with the help of computers. The molten material is then poured into the mold and allowed to cool down. Once it has cooled enough, it will be removed from the mold.
Some cores have double layering – the newly cooled core will be put into a bigger mold and material will be poured over it.
The next step is placing the core into a cover stock mold. The coverstock mold has a pin to which the core will be attached. The material poured over the core can have a thickness of 1 or 2 inches, depending on the design.
The last step to making the bowling ball is filling the gaps in the coverstock mold, then shaving off the excess to achieve the desired size. Sanding and smoothing is done afterwards for a highly-polished, lane-ready, bowling ball.