Types of Bowling
The outer shell of the bowling ball is known as the coverstock. The material of the
coverstock greatly determines how a ball will roll. In general, the harder the coverstock, the straighter the ball
will roll down the lane.
To be able to say what most bowling balls are made of, you would first have
to determine what year you were talking about.
Over the past twenty years, bowling balls have been made from a variety of materials. In the
1960's a hard plastic was used.
By the 1970's polyester balls had become popular and are still widely used today. Many times
when you get a ball from the alley, it is a polyester ball.
Urethane was used to build bowling balls by the 1980's but it was quite costly.
The first resin particles were added to urethane coverstocks in the 1990s. The resin particle
additive increased the friction between the balls and the lane, and increased the hook potential of the ball.
Resin balls are stronger than bowling balls made of other materials. The balls are known for
their sharper hooks and greater power, which gives them greater strike potential.
The resin balls evolved into particle balls when manufactures added ceramics and glass. The
added textures increased friction and gave the ball more grip in oil.
Bowling balls may seem simple to the common eye, but they are much more than solid spheres with
finger holes in them.
The circumference of the average bowling ball is usually between 26.704 and 27.002 inches. The
balls have varying weights to accommodate the varying strengths of many consumers. A bowling ball can weigh from 6
pounds to 16 pounds.
Three holes encompass the common bowling ball; two are for the fingers, and one is for the
thumb. There may also be a fourth, non-gripping hole (balance hole) in the bowling ball, which is used to fine-tune
the ball's reaction.
According to ABC/WIBC rules, a maximum of twelve holes are allowed in the ball; five holes (one
for each finger and thumb) for gripping purposes, five small vent holes (one for each gripping hole) to prevent
popping at the release point, one hole for balance purposes, and a small "mill" hole to check the hardness of the
coverstock just below the surface of the ball.
Make sure you are following the rules (e.g. appropriate hole size, distance between the holes)
if you want to drill additional holes in your ball.