Bowling Pin



Background

The first recorded reference to a game in which a ball is thrown at pins dates from 300 A.D. The reference comes from Germany where the game was part of a religious ceremony practiced by monks. During the ceremony, the pins signified the bowler's sins, which were to be struck down with a ball. Once discovered, bowling spread in various forms throughout Europe. In 1366, King Edward III of England is said to have outlawed any form of bowling (apparently it was distracting his troops).

In the early 1800s, the modern game of bowling with nine pins first appeared in the United States. There was not any standardization of the game and regional rules and specifications prevailed until 1895. At that time, restaurateur Joe Thum assembled representatives of various bowling clubs in New York City and created the American Bowling Congress (ABC).

The pins used in this early competition and for another half century were made from a single block of hard rock maple. These solid pins were durable enough and were simple to manufacture. The only significant drawback was that, with the varying density of wood, the weight of an individual pin was difficult to standardize. Then in 1946, American Machine and Foundry purchased the patent for an automatic pin setter and began producing a machine that would both popularize the game and change the way bowling pins were made. The new machine was not an immediate success. Bowling alleys had plenty of pin boys to reset the lanes, and the original machinery was relatively undeveloped. However, patrons enjoyed the speed of the new pin setters, and the machines could work long hours without rest. As the automatic pin setters became more widespread, a new problem arose. The pin setters were much harder on the pins than human hands had been, so the pins began splintering and cracking much more rapidly. In turn, the splinters from the pins were fouling the machinery of the pin setters.

In 1954, Vulcan Manufacturing produced the first pin to address the problem, the Vulcanate. Vulcan sawed a standard solid pin in half before its final shaping and glued a flat piece of maple between the halves. With this design, Vulcan could drill wood out of the center piece as needed to reduce the pin's final weight. The design also presented more edge grain to the outside of the pin, making the pins more resistant than the solid wood ones. That same year Henry Moore introduced a plastic-coated pin. As with the pin setter, the new coating was not immediately embraced by the bowling industry. The liquid plastic used in Moore's pin added significant weight and chipped easily. However, the concept behind the pin design was sound and soon manufacturers began searching for a lightweight and durable coating. Even the lightest of coatings added weight to the pins, which decreased scoring, so manufacturers moved away from solid maple and began to follow Vulcan's example of gluing smaller pieces together into the shape of a pin. By 1961, the solid pin had disappeared altogether.

Raw Materials

Core

As mandated by the American Bowling Congress and the Women's International Bowling Congress (ABC/WIBC), all bowling pins are made "of new (unused), sound, hard maple." Other materials may be used if they are given ABC/WIBC approval. The maple used is harvested above the 45th parallel, which runs through the northernmost states of the United States, above the areas where high mineral concentrations lessen the wood's density. Other core materials have been tried. In the late 1960s, manufacturers attempted to further the lamination concept by using particle lumber. Particle lumber is made by shredding wood, mixing it into a bonding agent, and pressing it into shape. The problem was that a dense mixture made the pins durable but low scoring, while light pins had the opposite problem. A polypropylene-fiberglass foam core known as a dykehouse core was also attempted. The foam was molded in two pieces, top and bottom, and the halves were fitted over a wooden dowel. Durability tests were impressive, but the project never developed into production.

Coating

When pins were made of solid blocks of maple, they were simply coated with a layer of white lacquer and finished with a layer of clear lacquer. The advent of the automatic pin setter spurred a need for more durable coatings, and the first successful one was ethylcellulose. Ethylcellulose coating was a seven-layer process. Pins were first dipped into a coat designed to seal the pores of the wood and then into one designed to provide better adhesion for the following layers. Then five layers of ethycellulose were applied. After the first layer, a nylon mesh sock was stretched over the pin where it acted like iron reinforcing bars in concrete or like straw in adobe brick, providing a structure for the ensuing layers.

The two coatings in use today are nylon and DuPont's Surlyn. Nylon has the advantage of being more forgiving in the molding process and having a lower cost than Surlyn. But cores must be dipped in latex to prevent the nylon from cracking, and nylon does not provide the same rigidity as Surlyn.

Design

The three considerations in designing a bowling pin are durability, scoring, and sound. The durability of pins has been vastly improved with the use of multi-piece cores and more resilient coatings. Multipiece cores are stronger and more durable than durable single blocks because of the way in which wood grows. A tree grows larger in layers or rings, each ring following the contours of the one under it. If the previous ring had a kink or curve in a certain spot, the next ring will also have that kink or curve, as will all the following rings. When you use a single block of wood, all of the layers in that wood will flex and eventually break in the same spot because they are all shaped the same, but if you take several small pieces and glue them into a block, each piece has its natural bends and weak spots in a different place, so each reinforces the other. An additional benefit of this method for bowling pins stems from the way in which the rings hold to one another. When a tree is in its natural state, its cross section is a series of concentric rings. Once milled into lumber, the cross section only contains portions of the rings, so it more closely approximates stacked sheets of cardboard. If you were to push against the side of a stack of cardboard, each sheet would be fairly rigid but each would slide out of the stack fairly easily, and you could lift off the top sheets with no trouble at all. If you were to press on the top of the stack, you could not easily split it in half but it would compress with little effort. This is exactly the situation with bowling pins. The old solid pins would dent on the face of their grain layers, and the large, flat layers would peel and split at the edge. Gluing together several pieces of wood gives the compression resistant advantage of presenting all edge grain to the outside of the pin, but because no one layer runs all the way through the pin, they are less prone to splitting.

Scoring and sound are both shaped by bowler's preferences and are primarily controlled by the core material. A bowling pin's whole purpose is to fall over. If it never falls over, the game becomes far less interesting. Although an obvious solution to the problem of durability would be to make a pin of a material stronger than wood, such as steel, most other materials are too heavy, so they do not fall over as readily as bowlers have come to expect. What has discouraged the use of many other materials, though, is

A bowling pin is a complex assembly of several maple wood pieces; each made of still smaller pieces. Each sub-assembly is glued and clamped into a pressurized mold to build it into the next larger piece.
A bowling pin is a complex assembly of several maple wood pieces; each made of still smaller pieces. Each sub-assembly is glued and clamped into a pressurized mold to build it into the next larger piece.
sound. The distinctive sound of pins crashing is part of the aura of the game, and that sound comes from wood. Presently, no other material has been able to match it.

The Manufacturing
Process

A bowling pin is a complex assembly of several maple wood pieces; each made of still smaller pieces. Each sub-assembly is glued and clamped into a pressurized mold to build it into the next larger piece. Lumber is dried in large kilns for 8-10 days before being shipped to the plant. When it reaches the plant, entire planks are cut at once into strips and then into blocks of specific size by multi-bladed automatic saws.

Core

Coating

Byproducts/Waste

Much of the wood used in the manufacture of bowling pins is itself a byproduct. The flooring industry mills thousands of board feet of maple every year. Because consumers prefer light-colored wood, the darker parts of the lumber are trimmed. Since a bowling pin is coated, color does not matter. Mills have begun to trim these pieces to the size used in pins, so what had been scrap is now a useful product.

Quality Control

The ABC/WIBC sets strict standards for pin height, weight, moisture content, coating thickness, center of gravity, and myriad other details. Each new pin design must meet these standards and must pass specific durability field tests. The manufacturer inspects each block of wood before it enters the assembly process. Pieces with knots, cracks, mineral deposits, or irregular grain are rejected. Once in use, a pin will last six months or so before it needs to be patched or recoated. Afterwards, it will last another six months before breaking. Most breaks happen in the thin area just below the top called the neck, where the whipping action of being knocked over flexes the wood by as much as 0.25 in (0.63 cm).

The Future

Maple has been the core material of choice for bowling pins for well over 200 years. Despite experiments with such diverse materials aluminum, plastic, and magnesium, nothing has been found to provide the durability, sound, and scoring range of maple.

Where to Learn More

Books

Borden, Fred and Ackerman, John. Bowling. Madison, WI: Brown & Benchmark, 1997.

Stallings, Howard. The Big Book of Bowling. Salt Lake City: Gibbs Smith, 1995.

Steele, H. Thomas. Bowl-O-Rama: the visual arts of bowling. New York: Abbeville Press, 1986.

Williams, Donald. The Bowling Trivia Book. Novi, MI: Williams Bowling Group, 1995.

Other

International Bowling Museum and Hall of Fame. http://www.bowlingmuseum.coml .

Michael Cavette



Also read article about Bowling Pin from Wikipedia

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