Stupid Question ™
Dec. 31, 1998
By John Ruch
Q: How do coin-operated pool tables tell the difference between the cue ball and the rest of the balls?
A: In pool, you knock balls out of play by sinking them into pockets on the table. You do this by hitting them with a cue ball. The cue ball isn’t supposed to be pocketed—if it is, it’s a “scratch,” and the cue ball is retrieved from the pocket and returned to play.
“Coin-op” tables make money by storing pocketed balls in a little pen that opens only after being fed more quarters. But they also have to follow the rules of the game and return a pocketed cue ball.
How do they do it? Usually with magnets. Sometimes with size.
When a ball is pocketed on a coin-op table, it goes down a chute and onto a metal track. The track consists of three parallel rails, making two separate tracks. Any pocketed ball at first runs on one set of tracks, which leads to the storage pen. Various mechanisms are used to force the cue ball over onto the other set of tracks, which leads to the return slot.
As the folks at Edison Billiard Table and Cue Manufacturing in Edison, Ohio informed me, “They don’t have a little man in there.”
The preferred way is to load the cue ball with steel and use a magnet to pull it over onto the second track. The favorite type is the “cat’s eye,” which has a steel bearing inserted into a drilled hole, which is then plugged and ground smooth.
Another kind, the “mudball,” has steel particles mixed into the rosin that is used to form the cue ball. According to Ken Rupp, owner of Columbus, Ohio’s Billiards Plus, mudballs can have a slightly uneven surface and balance, making them unpopular with serious players.
About 25 years ago, the Valley company got a patent on magnetic systems, and other companies had to innovate. One method is using an oversize cue ball (2 3/8 inches as opposed to the standard 2 ¼ inches) just big enough to catch on a spring that flings it over onto the second track.
Another is using a heavier cue ball that tips a tiny scale and dumps the ball onto the second track.
All these systems have the drawback of a slightly screwy cue ball, and all of them—to pool players’ delight—will occasionally return a regular ball.
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An Oct. 22 question about the origin of the image of a poor person wearing a barrel left me stumped.
Here’s a new factoid, from Patricia B. Mitchell’s 1993 book “Yanks, Rebels, Rats & Rations: Scratching for Food in Civil War Prison Camps.” During the war, starving prisoners in New York’s Elmira Prison ate a dog. As punishment, they were made to wear “barrel shirts”—pork barrels with the ends removed—with signs reading, “I ate a dog.” It was apparently a common punishment, with signs also reading, “I am a thief,” “I am a liar,” etc.