Re: Are baseballs and wood baseball bats made differently now than 30 years ago

Hi Jason, Major League Baseballs are tested for their coefficient of restitution at a fixed speed of something on the order of 60 miles per hour (I don't have the exact number available) and according to the MLB the range of "bounciness" has remained the same for many years. The problem is that most baseball collisions occur at much higher speeds. Although the power-fest of the 1987 season caused many people to wonder if something the balls were being wound tighter. There is not much scientific evidence that is available to the public.

Here is just one article I found on Androstenedione use by Mark McGwire. Many medical doctors and sports reporters have taken issue with the use of Androstenedione by athletes for performance enhancement. ESPN went into great detail on the topic during the homerun race.

Onto something I can say a little more definately:

Wooden baseball bats are made by the same techniques used since the turn of the century. Some advanced have been made in the machinery used.

White Ash wood is used for Major Leaugue Baseball bats. The wood primarily comes from the northeast US. The supply source used to be from all around the US. I suspect this change was based on economics and not based on any study of bat performance.

Any bat that does not conform to recognized standards must be reviewed by the MLB. The biggest diameter bat allowed in MLB (and all levels of baseball I know) is 2.75 inches -- the biggest diameter being at the barrel of the bat.

The typical major leaguer uses a bat that is 34.5 inches long and weights between 30 - 32 ounces (just about 2 pounds). Most players have a bat that is very close to the 2.75 inches diamter, but to get the weight down, the handle off the bat is pretty thin -- usually about 1 inch in diameter.

Back in the 1940's and 1950's, players used bats that were much heavier (34 to 38 ounces). The bats were similar to modern bats except that the handle was thicker and the barrel was not as close to the maximum. As a result players did not suffer as many "sawed-off" bats, but did get more "sting" when they hit a ball off the sweet spot because they could not grip the bat as effectively.

A key legal change to bat design is the evolution of a cupped end. The barrel end of the bat is shaved away leaving a semi-circular indentation of up to 1 inch in depth. The intent of this change is to lower the weight of the bat and to change the swing-weight. Swing-weight is another term for the physics concept of first moment of the bat that is calculated by integrating the mass density times the bat length. A cupped bat is supposed to extend the "sweet spot" over a longer area of the barrel and move the sweet spot closer to the hands of the batter.

I have answered a few related questions on baseball bats that may help give you some information on the properties of baseball bats:

A search at MS_search on baseball bat will turn up quite a few results

Re: Physics of cheating in baseball

Re: Torque and a Baseball Bat

Re: How does the metal in golf clubs affect your golf game

You might also try a search on just baseball as well.

Some interesting links besides my own references (I hate when people only refer to their own work -- very unscientific)

www.amcity.com/louisville/stories/063097/story4.html

espn.sportszone.com/editors/nye/may97.html

Sincerely,

Tom "Home Run Watcher" Cull P.S. As usual I recommend The Physics of Baseball by Addair. He speaks about a 1940's army study on the collision properties of baseballs and goes into great detail about bats and hitting.