An official Major League baseball has 108 double stitches, for a total of 216 stitches.
These hand-sewn double stitches represent the final steps in the construction of a baseball, which is built from many constituent pieces.
Structure of a Baseball
The core of a baseball consists of a ball of cork surrounded by a thick black rubber membrane.
The next layer consists of a heavy red rubber covering, which is wrapped in several shells of wool yarn with various consistencies and thicknesses.
Closest to the core is a layer of 4-ply gray wool yarn, followed by 3-ply white wool yarn, all encapsulated in 3-play gray wool yarn.
The out interior layer of the baseball consists of white cotton yarn.
Finally, two figure-eight sections of white cowhide are wrapped around the ball in an interlocking fashion, and then sewn into place.
The cowhide is stitched into place using 88-inch waxed red thread.
As mentioned above, although the baseballs you might buy in a typical sporting goods store may very well have been sewn together using a machine, Major League baseballs are hand-stitched.
Major League baseball first standardized their ball in 1876 and adopted red as the standard color for stitches in 1934.
There has been much speculation over why MLB chose red, but the general consensus seems to be that it aids in visibility for batters and fielders, alike.
(Though you have to wonder if pitchers wouldn’t prefer some subterfuge.)
Prior to that time, the National League used black thread intertwined with read, while the American League combined blue and red thread for their stiches.
Through 1975, Major League baseballs were manufactured by Spalding, whose founder was A.G. Spalding, former MLB pitcher and the inventor of the first standardized ball.
Then, in 1976, MLB switched affiliation and has used Rawlings baseballs ever since.
Today, all Major League baseballs are made at Rawlings facilities in Costa Rica, with some one million balls used by MLB teams each year.