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A Real Corker

Allegations of bat tampering flew throughout the 1987 baseball season. Yet, not since 1974--when the bat of the New York Yankees' Graig Nettles broke and several compressed rubber balls spill out--had a hitter been ejected for using a doctored bat. In response to the latest flurry of bat-related rhubarbs, Major League Baseball Commissioner Peter Ueberroth granted managers permission to confiscate one bat from an opponent if they suspected tampering.

In August, a representative from Ueberroth's office asked NIST experts on non-destructive evaluation to do a quick study of ways to detect illegal cork or rubber cores bored into the heads of bats. A handful of scientists and engineers from NIST's Gaithersburg, Md., headquarters, and Boulder, Colo., facility contributed to the effort.

With four bats (two normal bats and two with cork cores about two pencil widths in diameter) supplied by Major League Baseball, the NIST team assessed a variety of approaches-ultrasound and several types of x-ray devices, including a -CAT scanner. Two of the bats--one "loaded" and the other not--were even taken to Boulder Memorial Hospital for -diagnostic x-rays, which were viewed from several carefully determined perspectives. The cost of the service was $30.

Medical x-rays were probably the best imaging tools for non-destructive tests of baseball bats. They were deemed the quickest and most practical option, since most ball parks were equipped with x-ray machines for diagnosing player injuries. In contrast, measurements made with ultrasound were less definitive, and the data took longer to collect and interpret.

On September 1, 1987, the day after NIST researcher Ray Schramm took two bats in for x-rays at Boulder Memorial, Houston Astros outfielder Billy Hatcher was ejected from a game against the Chicago Cubs for using a corked bat. No x-rays were needed in this case. Hatcher hit a broken-bat single, and one of the shards ended up in the hands of Cubs third baseman Keith Moreland, who held up the remnant for all to see. Said umpire John McSherry: "The bat was hollowed out at the barrel and had three or four inches cork inside it."

Hatcher, the Astros leading hitter, said he was using a borrowed bat because all his bats were broken. He maintained that he did not know it was corked. He was suspended for 10 days, just as his team was challenging for a divisional title.

Reflection: Why cork the bat?
"At the time we had several discussions of the physics of corking bats. Was it a weight change that allowed a faster swing due to change in moment of inertia? Was it a change in coefficient of restitution that imparted more energy to the ball? I don't believe we ever came to a consensus. My opinion (and only that) is that any effect was strictly psychological."
--Ray Schramm, retired NIST researcher (deceased)


-Baseball bat images from the NIST study

NIST's Material Reliability Division (site of much of NIST's research on methods of non-destructive evaluation)