Blog: The history of a tennis ball

“The introduction of new elastomers and plastics has had a profound influence on many sports. New materials cannot be used indiscriminately; however, attention must be paid to specifications, rules and regulations governing the various sports and games.”

—Robert Haines, “The Sporting use of polymers,” Shell Petrochemicals, 1993.

AKRON—When I began to examine the manufacturing of a tennis ball, I wanted to understand the history behind it. I thought I would understand the present more if I could understand the past, but I failed to recognize the big difference between the sporting arena and other sectors of the rubber and plastics industry.

Technology allows us to create more efficient and better products, within regulations of safety. However, with sports, the regulation involves keeping so much the same. If a record were broken because of a more efficient tennis ball, is that player really better than one from past generations?

How do you make it fair? You have a regulating body—in this case, the International Tennis Federation—that keeps everything organized and efficient in the tennis world.

When starting my research, I reached out to the ITF to see if I could use the manufacturing process information on its website —ITFTennis.com—and the organization did me one better: it put me in contact with the man who wrote it.

Robert Haines, now retired, started his career on the technical side of tennis ball manufacturing in 1963, where he worked for Dunlop, which took over Slazenger in 1958. He continued there until 1992, then became a technical consultant to the ITF at its headquarters in London. He is now retired from consulting, but he still took the time to exchange multiple emails with me and send some great articles he has written over the years on the subject. I could have not asked for a better technical look of the history of the tennis ball.

Haines gave me so much information that I could write four blog entries, but I am going to break it down into some highlights. If you want a detailed explanation of the different stages of tennis ball manufacturing, click here.

“The special properties of rubber have long made it attractive for use in sports and games,” Robert wrote in Developments in Rubber and Rubber Composites in 1983.

Tennis ball manufacturing is by no means new. Robert said Slazenger started making tennis balls in the 1880s and Dunlop in the 1920s. Then in 1958, they merged into one company.

Later in the article, he noted that tennis balls were made solely of rubber, but the “wearing and playing properties of the balls were improved by covering them with flannel stitched around the rubber ‘core.' ”

He added that originally, core manufacturing was based on a “clover leaf” principle where an uncured rubber sheet was stamped into a shape resembling a three-leaf clover, and this was then assembled into a rough spherical shape by machinery.

This process was used for many years until “the precision of the game demanded a higher degree of uniformity (particularly relating to wall thickness) than could be obtained with the clover-leaf method,” he wrote. When he authored the piece in 1983, he said it was usual to compression mold two separate half-shells, which were assembled together to produce a core. Then, the original flannel cloth was replaced by special ‘Melton' cloth made specifically for the purpose of the stitching, which has been replaced by a vulcanized rubber seam.

According to the ITF website manufacturing process information, this remains the standard.

Until recently, the ITF said tennis balls mainly were manufactured in Europe and the U.S.; however the majority of production now takes place in the Far East. Robert added that Dunlop made tennis balls in its tire factories, which had expanded into France, Germany, Australia, South Africa, Japan and the U.S. Because of strong competition for Dunlop balls in the U.S., a new core compound formulation and cloth specification was developed in the United Kingdom, and a new factory was built in Hartwell, Ga. in 1973, Robert said. This plant was closed in 1992, and the equipment transferred to the Philippines, where production started in 1996.

Companies began setting up shop in the Far East because of the significantly lower cost of labor, Robert said, because the ball manufacturing process is a labor intensive.

“To illustrate this, much handwork is involved, and in the process and components of the ball, and the ball itself when finished, are subject to four separate heating and cooling operations,” he wrote in my email interview.

The properties of tennis balls became more tightly controlled when the so-called “Stevens Machine” was developed in the 1920s, Robert said.

This hand-worked table-top machine measured the ‘compression' of a ball—that is its change in diameter under a static load. This led the ITF to establish more complete specifications for balls, which initially only covered mass, size and rebound, Robert added.

This existed virtually unchanged until 1966 when a measurement for “return compression” was introduced with a slightly modified Stevens, which measured the elasticity of a ball by how well its diameter recovered from the original compressive loading. This measured the hysteresis of the ball and was necessary due to the development of balls that were not pressurized in the 1960s.

Specifications stayed consistent until the early 2000s, Robert said, when it was expanded to include slightly harder and softer balls for special playing conditions as well as for balls with a larger diameter and a specification for use in high altitudes.

Special balls recently have been developed and specified for children and recreational players and are of three types: standard construction, cut foam and molded foam, each having different properties.

As with all manufacturing, there is more than meets the eye. If you want to read an interesting article about the 50,000 mile journey a Wimbledon tennis ball takes to get to the competition, check out this link.

Are you looking for more information about the history of tennis balls or how they are manufactured? Reach out to me by email at [email protected] or on Twitter @jenniferkarpus.