Baseballs manufactured for Major League Baseball (the "League") for use in championship games (including the All-Star Game and World Series games) shall be made in accordance with the following specifications:
A. Pill. The pill of the baseball shall consist of a compressed cork sphere surrounded by one layer of black rubber and one layer of red rubber. The pill shall weigh .85 ( .05 ounces and shall measure 1.375 ( .010 inches in diameter.
B. Center. The center of the baseball shall be spherical and shall be produced by winding three layers of woolen yarn and one layer of poly/cotton yarn around the pill.
1. First Wind. The first wind shall consist of a 4-ply gray woolen yarn containing approximately 85% wool and 15% other fibers, sized to 600 grains/50 yard reeling. The total size and weight of the center (including the cushion cork pill) after the first wind shall be: circumference- 7 8/16 ( 1/16 inches and weight- 2 14/16 ( 1/16 ounces.
2. Second Wind. The second wind shall consist of a 3-ply white woolen yarn containing approximately 85% wool and 15% other fibers, sized to 450 grains/50 yard reeling. The total size and weight of the center after the second wind shall be: circumference- 8 ( 1/16 inches and weight- 3 6/16 ( 1/16 ounces.
3. Third Wind. The third wind shall consist of a 3-ply gray woolen yarn containing approximately 85% wool and 15% other fibers, sized to 335 grains/50 yard reeling. The total size and weight of the center after the third wind shall be: circumference- 8 12/16 ( 1/16 inches and weight- 4 2/16 ( 1/16 ounces.
4. Fourth Wind. The fourth wind shall consist of a white 20/2 poly-cotton 50/50 blend yarn. The total size and weight of the center after the fourth wind shall be: circumference- 8 12/16 to 8 13/16 inches and weight- 4 6/16 to 4 7/16 ounces.
5. Cement Coating. A cement coating shall be applied to the center after the fourth wind and to the covers to hold the covers onto the center during the sewing operation. The size and weight of the center after application of the cement shall be: circumference- 8 12/16 to 8 13/16 inches and weight- 4 7/16 to 4 8/16 ounces.
C. Covers. Covers shall be of grade #1 special alum tanned, full-grain, cowhide leather and shall be clear and well matched in color and texture. Grade #1 special alum tanned, full-grain, horsehide leather may be substituted for cowhide with the prior approval of the League. Covers shall be sewn onto the centers with double stitch 10/5 red thread. The weight of the covers shall be approximately .625 ounces per pair and the thickness of the covers shall be from.046 to .056 inches.
1. Seam Height. The seams of finished baseballs shall be rolled or pressed so that they are of even height and reasonably flat against the cover surface.
D. Weighing and Measuring Finished Baseballs. The circumference of finished baseballs shall be measured using a steel tape in gradations of 1/16 of an inch with 2 lbs. of tension applied to the tape. The circumference shall be determined by measuring twice over two seams and once over four seams, and thereafter averaging the three measurements. Finished baseballs shall measure 9.125 inches ( .125 inches in circumference and shall weigh 5.125 ounces ( .125 ounces.
E. Coefficient of Restitution. The coefficient of restitution, or resiliency, of a finished baseball shall be determined by measuring the ratio of its rebound velocity to its impact velocity when the baseball is fired from an air cannon or similar device at a speed of 85 feet per second against an immobile impact surface constructed of northern white ash (baseball bat material), 2.5 inches thick, mounted onto a 12 inch square steel reinforced concrete column directly anchored to the ground. The coefficient of restitution of the baseball shall be between .514 and .578.
All test measurements of coefficient of restitution shall be made on equipment which is satisfactory to the League and which has been designed to assure a high degree of accuracy.
All test firings shall be made at an angle which is normal to the impact surface.
Baseballs to be tested for coefficient of restitution shall first be stored for at least five full days at 70( F and 50% relative humidity within ( 5% in relative humidity and within ( 5( in temperature.
For the purposes of this Agreement, the League approves the following measurement system: The impact and rebound velocity of a baseball shall be measured using a system of dual, light sensitive, solid state ballistics sensing screens connected to a pair of computing digital chronographs. The light screens shall be positioned 12 inches apart. The distance from the muzzle of the air cannon to the first light screen shall be a minimum of eight feet. The second light screen shall be at least six inches, but not more than 10 inches, from the impact surface. The time required for the ball to pass from the first light screen to the second while moving toward the impact surface shall be used to compute the impact velocity of the baseball. The time required for the ball to travel from the second light screen back to the first after collision with the impact surface shall be used to measure the rebound velocity of the baseball. The computing digital chronographs activated by the light screens shall be accurate within ( .05%.
F. Appearance of Finished Baseball. Finished baseballs shall be reasonably free of cosmetic defects.