Although Jeffrey Di Tullio of MIT only recently thought of putting dimples in baseball bats, golf balls have had dimples (accidentally, at least) for hundreds of years. In the early years of the game in Scotland, the balls were made of wood, and players noticed that older balls-those that had dents from being hit many times-tended to fly farther than new ones, he said
There's a reason that Little League coaches tell hitters to hold their bats with the trademark facing up. The trademark is burned into the bat 90 degrees away from the grain, so when the batter holds the bat with the trademark up, "you have the strongest part of the bat facing the pitcher" so the ball will be hit on the grain, thus reducing the likelihood that the bat will crack, according to Bill Williams, vice president of advertising and public relations for Hillerich and Bradsby Co. of Louisville, KY, makers of the Louisville Slugger.
About 190,000 of the one million wooden bats made each year by Hillerich and Bradsby are purchased for use by the 28 major league and 150 minor league teams in professional baseball, he said. Teams pay $22 to $23 apiece for bats for their players, each of whom goes through 80 to 90 bats a year, he added.
Major league baseball doesn't use metal bats because they make the ball fly significantly faster and farther than wooden bats, said George Manning, vice president of technical services for Hillerich and Bradsby. Because metal bats are hollow, the bat's elastic deformation is greater, causing the ball to "jump" off the bat to a greater degree than for wood, he explained. When the NCAA introduced metal bats for college play in the early 1970s, team batting averages shot up by an average of 30 points and home run production more than doubled, he said.
Aluminum bats can cost $80 to $100 compared to about $20 for a wooden bat, but because they don't splinter, they last much longer. Metal bats last for about one season of daily use; after that, metal fatigue in the form of minute cracks sets in; the bat doesn't shatter, but eventually "it feels like a paper clip," Mr. Manning said.
The effective hitting surface for an aluminum bat is longer near the handle compared to a wooden bat, making an aluminum bat much more suitable for hitting inside pitches, according to a study by P. Brancazio presented at an American Physical Society meeting and quoted in Keep Your Eye on the Ball by Robert G. Watts and A. Terry Bahill.
A version of this article appeared in the March 2, 1994 issue of MIT Tech Talk (Volume 38, Number 24).