The theory of the bowling ball spinner is simple. Over time, bowling balls get dented and their finishes, textures, and surfaces get scratched and pitted. A groove- called a ball track- also emerges, representing the path that the ball most frequently takes as it rolls. With constant use, this ball track can actually stop a ball from rolling as it should. The scratches increase the friction and the ball track influences the way your bowling ball moves. The end result? When your ball hits the pins, it hits them with much less energy and impact than it should.
That's where the spinner comes in. It acts like a sander, grinding away the scratches and removing the ball track, leaving your bowling ball good as new. A spinner typically has a variety of grit that it can use on the bowling ball, with different grits used to produce different types of surface friction. The more coarse the grit, the less smooth the resulting finish, and the greater the surface friction. With smaller grit, the polish is more even, resulting in a smoother roll.
Ball spinning is also useful if you frequently bowl on oily lanes. The oil from these lanes can seep into the bowling ball, giving it a shiny, oiled appearance over time. A light sanding polish from a ball spinner removes this oil. Similarly, if you are changing lanes and want the surface of your ball to better suit the condition of the new lane, choose the desired surface friction and use a ball spinner accordingly.
Most bowling supplies are harmless to a new user. A bowling ball spinner, however, is potentially dangerous- unless you know how to use it. Most come with strict instructions and warnings. Furthermore, an inexperienced user could easily ruin his or her bowling ball by over-grinding it with courser grit than they should be using. Is it right to offer spinners alongside the bowling supplies most online bowling stores sell? Yes, because of the benefit to people who know how to use them. They are a bowling supply, after all - just don't try spinning your bowling ball without talking to a professional first.