In baseball, a corked bat is a specially modified baseball bat that has been filled with cork or other lighter, less dense substances to make the bat lighter. A lighter bat gives a hitter a quicker swing and may improve the hitter's timing. Despite popular belief that corking a bat creates a "trampoline effect" causing a batted ball to travel farther, physics researchers have shown that this is not the case. In Major League Baseball, modifying a bat with foreign substances and using it in play is illegal and subject to ejection and further punishment.
Construction of corked bats
To cork a bat, a hole approximately 1/2-inch (12.5 mm) in diameter is drilled down through the thick end of the bat roughly six inches deep. Crushed cork, bouncy ball, sawdust, or other similar material is compacted into the hole and the end is typically patched up with glue and sawdust. However, this weakens the bat's structural integrity and makes it more susceptible to breakage, even more so if the cork is placed beyond roughly six inches into the bat. Corked bats are typically discovered when they break during play.
Corked bats were tested in the 2007 season of MythBusters where it was found that the cork was detrimental to the bat's performance.
Corked bats in Major League Baseball
Using a corked bat in Major League Baseball is in violation of Rule 6.03 (a)(5), which states
A batter is out for illegal action when:
(5) He uses or attempts to use a bat that, in the umpire’s judgment, has been altered or tampered with in such a way to improve the distance factor or cause an unusual reaction on the baseball. This includes bats that are filled, flat-surfaced, nailed, hollowed, grooved or covered with a substance such as paraffin, wax, etc.
It has been a popular belief that the material used to cork a bat creates a "trampoline effect," causing a ball hit with a corked bat to travel farther than one hit with an uncorked bat. Research has shown this not to be the case. Another perceived advantage of using a corked bat is its effect on the bat's weight. Corking a bat causes the bat to be lighter, which in turn allows the batter to swing it more quickly. However, the reduction in weight negatively affects the velocity of the ball as it leaves the bat, effectively cancelling out the advantage gained from a quicker bat speed. A lighter bat can, however, create an advantage by allowing the batter to delay a swing for a fraction of a second, which would allow for more accuracy.
History of use in Major League Baseball
Since 1970, six players have been caught using corked bats. The following table summarizes these events:
|Sammy Sosa||Chicago Cubs||June 3, 2003||Eight games||Corked bat||Bat was meant to only be used in batting practice|
|Wilton Guerrero||Los Angeles Dodgers||June 1, 1997||Eight games||Corked bat||None|
|Chris Sabo||Cincinnati Reds||July 29, 1996||Seven games; Reds fined $25,000||Corked bat||Borrowed bat from unnamed teammate|
|Albert Belle||Cleveland Indians||July 15, 1994||Seven games||Corked bat||None|
|Billy Hatcher||Houston Astros||August 31, 1987||Ten days||Corked bat||Borrowed bat from pitcher (Dave Smith)|
|Graig Nettles||New York Yankees||September 7, 1974||Ten days||Six super balls in bat||Received bat as a gift from a fan|
In 2010, Deadspin reported that Pete Rose used corked bats during his 1985 pursuit of Ty Cobb's all-time hits record. Two sports memorabilia collectors who owned Rose's game-used bats from that season had the bats x-rayed and found the telltale signs of corking. Rose had previously denied using corked bats.
- Russell, Daniel (2011). "What about corked bats?". Physics and Acoustics of Baseball & Softball Bats. Penn State University. Retrieved 2019-08-01.
A bat which has less mass, and especially which has a lower moment of inertia, may be swung faster.
- Solomon, Christopher (2011-06-23). "The physics of cheating in baseball". smithsonian.com. Smithsonian Institution. Retrieved 2019-08-01.
- Nathan, Alan M.; Smith, Lloyd V.; Faber, Warren L.; Russell, Daniel A. (2011). "Corked bats, juiced balls, and humidors: The physics of cheating in baseball". American Journal of Physics. 79 (6): 575–580. arXiv:1009.2549. doi:10.1119/1.3554642. Retrieved 2019-08-01.
- Major League Baseball. Official Baseball Rules, 2019. Rule 6.03 (a)(5) § Batter Illegal Action.
- Emerging Technology from the arXiv (2010-09-16). "The misleading myth of the corked bat". MIT Technology Review. MIT. Retrieved 2019-08-01.
- "Corked bat-related penalty reduced by one game", ESPN.com news services, June 11, 2003 (accessed March 6, 2009)
- "Sosa gets eight games, appeals Archived 2004-10-18 at the Wayback Machine", MLB.com (accessed June 28, 2006)
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- Petchesky, Barry (June 8, 2010). "This Is Pete Rose's Corked Bat". Deadspin. Gawker Media. Archived from the original on 2016-06-16. Retrieved 16 June 2016.
- Littmann, Chris (8 June 2010). "Corked Bats Reportedly Belonging to Pete Rose Come to Light". SBNation. Retrieved 16 June 2016.
- "Pete Rose interview". Cincinnati Enquirer. January 13, 2004. Retrieved 16 June 2016.[permanent dead link]