Interchangeable parts

The invention: 



A key idea in the late Industrial Revolution, the

interchangeability of parts made possible mass production of

identical products.





The people behind the invention:



Henry M. Leland (1843-1932), president of Cadillac Motor Car

Company in 1908, known as a master of precision

Frederick Bennett, the British agent for Cadillac Motor Car

Company who convinced the Royal Automobile Club to run

the standardization test at Brooklands, England

Henry Ford (1863-1947), founder of Ford Motor Company who

introduced the moving assembly line into the automobile

industry in 1913








An American Idea



Mass production is a twentieth century methodology that for the

most part is a result of nineteenth century ideas. It is a phenomenon

that, although its origins were mostly American, has consequently

changed the entire world. The use of interchangeable parts, the feasibility

of which was demonstrated by the Cadillac Motor Car Company

in 1908, was instrumental in making mass production possible.

The British phase of the Industrial Revolution saw the application

of division of labor, the first principle of industrialization, to capitalist directed

manufacturing processes. Centralized power sources were

connected through shafts, pulleys, and belts to machines housed in

factories. Even after these dramatic changes, the British preferred to

produce unique, handcrafted products formed one step at a time using

general-purpose machine tools. Seldom did they make separate components

to be assembled into standardized products.

Stories about American products that were assembled from fully

interchangeable parts began to reach Great Britain. In 1851, the British

public saw a few of these products on display at an exhibition in

London’s Crystal Palace. In 1854, they were informed by one of their

own investigative commissions that American manufacturers were

Stories about American products that were assembled from fully

interchangeable parts began to reach Great Britain. In 1851, the British

public saw a few of these products on display at an exhibition in

London’s Crystal Palace. In 1854, they were informed by one of their

own investigative commissions that American manufacturers were

building military weapons and a number of consumer products

with separately made parts that could be easily assembled, with little

filing and fitting, by semiskilled workers.

English industrialists had probably heard as much as they ever

wanted to about this so-called “American system of manufacturing”

by the first decade of the twentieth century, when word came

that American companies were building automobiles with parts

manufactured so precisely that they were interchangeable.





The Cadillac



During the fall of 1907, Frederick Bennett, an Englishman who

served as the British agent for the Cadillac Motor Car Company, paid

a visit to the company’s Detroit, Michigan, factory and was amazed

at what he saw. He later described the assembling of the relatively inexpensive

Cadillac vehicles as a demonstration of the beauty and

practicality of precision. He was convinced that if his countrymen

could see what he had seen they would also be impressed.

Most automobile builders at the time claimed that their vehicles

were built with handcrafted quality, yet at the same time they advertised

that they could supply repair parts that would fit perfectly.

In actuality, machining and filing were almost always required

when parts were replaced, and only shops with proper equipment

could do the job.

Upon his return to London, Bennett convinced the Royal Automobile

Club to sponsor a test of the precision of automobile parts. A

standardization test was set to begin on February 29, 1908, and all of

the companies then selling automobiles were invited to participate.

Only the company that Bennett represented, Cadillac, was willing

to enter the contest.

Three one-cylinder Cadillacs, each painted a different color, were

taken from stock at the company’s warehouse in London to a garage

near the Brooklands race track. The cars were first driven around

the track ten times to prove that they were operable. British mechanics

then dismantled the vehicles, placing their parts in piles in the

center of the garage, making sure that there was no way of identifying

from which car each internal piece came. Then, as a further test,

eighty-nine randomly selected parts were removed from the piles

and replaced with new ones straight from Cadillac’s storeroom in

London. The mechanics then proceeded to reassemble the automobiles,

using only screwdrivers and wrenches.

After the reconstruction, which took two weeks, the cars were

driven from the garage. They were a motley looking trio, with fenders,

doors, hoods, and wheels of mixed colors. All three were then

driven five hundred miles around the Brooklands track. The British

were amazed. Cadillac was awarded the club’s prestigious Dewar

Trophy, considered in the young automobile industry to be almost

the equivalent of a Nobel Prize. A number of European and American

automobile manufacturers began to consider the promise of interchangeable

parts and the assembly line system.





Henry M. Leland



Cadillac’s precision-built automobiles were the result of a lifetime

of experience of Henry M. Leland, an American engineer.

Known in Detroit at the turn of the century as a master of precision,

Leland became the primary connection between a series of nineteenth

century attempts to make interchangeable parts and the

large-scale use of precision parts in mass production manufacturing

during the twentieth century.

The first American use of truly interchangeable parts had occurred

in the military, nearly three-quarters of a century before the

test at Brooklands. Thomas Jefferson had written from France about

a demonstration of uniform parts for musket locks in 1785. A few

years later, Eli Whitney attempted to make muskets for the American

military by producing separate parts for assembly using specialized

machines. He was never able to produce the precision necessary

for truly interchangeable parts, but he promoted the idea

intensely. It was in 1822 at the Harpers Ferry Armory in Virginia,

and then a few years later at the Springfield Armory in Massachusetts,

that the necessary accuracy in machining was finally achieved

on a relatively large scale.

Leland began his career at the Springfield Armory in 1863, at the

age of nineteen. He worked as a tool builder during the Civil War

years and soon became an advocate of precision manufacturing. In

1890, Leland moved to Detroit, where he began a firm, Leland &

Faulconer, that would become internationally known for precision

machining. His company did well supplying parts to the bicycle industry

and internal combustion engines and transmissions to early

automobile makers. In 1899, Leland & Faulconer became the primary

supplier of engines to the first of the major automobile producers,

the Olds Motor Works.

In 1902, the directors of another Detroit firm, the Henry Ford

Company, found themselves in a desperate situation. Henry Ford,

the company founder and chief engineer, had resigned after a disagreement

with the firm’s key owner,William Murphy. Leland was

asked to take over the reorganization of the company. Because it

could no longer use Ford’s name, the business was renamed in

memory of the French explorer who had founded Detroit two hundred

years earlier, Antoine de la Mothe Cadillac.

Leland was appointed president of the Cadillac Motor Car Company.

The company, under his influence, soon became known for its

precision manufacturing. He disciplined its suppliers, rejecting anything

that did not meet his specifications, and insisted on precision

machining for all parts. By 1906, Cadillac was outselling all of its

competitors, including Oldsmobile and Ford’s new venture, the

Ford Motor Company. After the Brooklands demonstration in 1908,

Cadillac became recognized worldwide for quality and interchangeability

at a reasonable price.





Impact



The Brooklands demonstration went a long way in proving that

mass-produced goods could be durable and of relatively high quality.

It showed that standardized products, although often less costly

to make, were not necessarily cheap substitutes for handcrafted and

painstakingly fitted products. It also demonstrated that, through

the use of interchangeable parts, the job of repairing such complex

machines as automobiles could be made comparatively simple,

moving maintenance and repair work from the well-equipped machine

shop to the neighborhood garage or even to the home.

Because of the international publicity Cadillac received, Leland’s

methods began to be emulated by others in the automobile industry.

His precision manufacturing, as his daughter-in-law would later

write in his biography, “laid the foundation for the future American

[automobile] industry.” The successes of automobile manufacturers

quickly led to the introduction of mass production methods, and

strategies designed to promote their necessary corollary mass consumption,

in many other American businesses.

In 1909, Cadillac was acquired by William Crapo Durant as the

flagship company of his new holding company, which he labeled

General Motors. Leland continued to improve his production methods,

while also influencing his colleagues in the other General Motors

companies to implement many of his techniques. By the mid-

1920’s, General Motors had become the world’s largest manufacturer

of automobiles. Much of its success resulted from extensions

of Leland’s ideas. The company began offering a number of brand

name vehicles in a variety of price ranges for marketing purposes,

while still keeping the costs of production down by including in

each design a large number of commonly used, highly standardized

components.

Henry Leland resigned from Cadillac during World War I after

trying to convince Durant that General Motors should play an important

part in the war effort by contracting to build Liberty aircraft

engines for the military. He formed his own firm, named after his favorite

president, Abraham Lincoln, and went on to build about four

thousand aircraft engines in 1917 and 1918. In 1919, ready to make

automobiles again, Leland converted the Lincoln Motor Company

into a car manufacturer. Again he influenced the industry by setting

high standards for precision, but in 1921 an economic recession

forced his new venture into receivership. Ironically, Lincoln was

purchased at auction by Henry Ford. Leland retired, his name overshadowed

by those of individuals to whom he had taught the importance

of precision and interchangeable parts. Ford, as one example,

went on to become one of America’s industrial legends by

applying the standardized parts concept.





Ford and the Assembly Line



In 1913, Henry Ford, relying on the ease of fit made possible

through the use of machined and stamped interchangeable parts,

introduced the moving assembly line to the automobile industry.

He had begun production of the Model T in 1908 using stationary

assembly methods, bringing parts to assemblers. After having learned

how to increase component production significantly, through experi-

ments with interchangeable parts and moving assembly methods in

the magneto department, he began to apply this same concept to final

assembly. In the spring of 1913, Ford workers began dragging car

frames past stockpiles of parts for assembly. Soon a power source

was attached to the cars through a chain drive, and the vehicles

were pulled past the stockpiles at a constant rate.

From this time on, the pace of tasks performed by assemblers

would be controlled by the rhythm of the moving line. As demand

for the Model T increased, the number of employees along the line

was increased and the jobs were broken into smaller and simpler

tasks. With stationary assembly methods, the time required to assemble

a Model T had averaged twelve and one-half person-hours.

Dragging the chassis to the parts cut the time to six hours per vehicle,

and the power-driven, constant-rate line produced a Model T

with only ninety-three minutes of labor time. Because of these

amazing increases in productivity, Ford was able to lower the selling

price of the basic model from $900 in 1910 to $260 in 1925. He

had revolutionized automobile manufacturing: The average family

could now afford an automobile.

Soon the average family would also be able to afford many of the

other new products they had seen in magazines and newspapers.

At the turn of the century, there were many new household appliances,

farm machines, ready-made fashions, and prepackaged food

products on the market, but only the wealthier class could afford

most of these items. Major consumer goods retailers such as Sears,

Roebuck and Company, Montgomery Ward, and the Great Atlantic

and Pacific Tea Company were anxious to find lower-priced versions

of these products to sell to a growing middle-class constituency.

The methods of mass production that Henry Ford had popularized

seemed to carry promise for these products as well. During

the 1920’s, by working with such key manufacturers as Whirlpool,

Hoover, General Electric, and Westinghouse, these large distributors

helped introduce mass production methods into a large number

of consumer product industries. They changed class markets

into mass markets.

The movement toward precision also led to the birth of a separate

industry based on the manufacture of machine tools. A general

purpose lathe, milling machine, or grinder could be used for a num-

ber of operations, but mass production industries called for narrow purpose

machines designed for high-speed use in performing one

specialized step in the production process. Many more machines

were now required, one at each step in the production process. Each

machine had to be simpler to operate, with more automatic features,

because of an increased dependence on unskilled workers. The machine

tool industry became the foundation of modern production.

The miracle of mass production that followed, in products as

diverse as airplanes, communication systems, and hamburgers,

would not have been possible without the precision insisted upon

by Henry Leland in the first decade of the twentieth century. It

would not have come about without the lessons learned by Henry

Ford in the use of specialized machines and assembly methods, and

it would not have occurred without the growth of the machine tool

industry. Cadillac’s demonstration at Brooklands in 1908 proved

the practicality of precision manufacturing and interchangeable

parts to the world. It inspired American manufacturers to continue

to develop these ideas; it convinced Europeans that such production

was possible; and, for better or for worse, it played a major part

in changing the world.







Henry Martyn Leland





Henry Martyn Leland (1843-1932) is the unsung giant of

early automobile manufacturers, launching two of the bestknown

American car companies, Cadillac and Lincoln, and influenced

the success of General Motors, as well as introducing

the use of interchangeable parts. Had he allowed a model to be

named after him, as did Henry Ford and Ransom Olds, he

might have become a household name too, but he refused any

such suggestion.

Leland worked in factories during his youth. During the

CivilWar he honed his skills as a machinist at the U.S. Armory

in Springfield, Massachusetts, helping build rifles with interchangeable

parts. After the war, he learned how to machine

parts to within one-thousandth of an inch, fabricated the first

mechanical barber’s clippers, and refined the workings of air

brakes for locomotives.

This was all warm-up. In 1890 he moved to Detroit and

opened his own business, Leland and Faulconer Manufacturing

Company, specializing in automobile engines. The 10.25-horsepower

engine he built for Olds in 1901 was rejected, but the single-

cylinder (“one-lunger”) design that powered the first Cadillacs

set him on the high road in the automotive industry. More

innovations followed. He developed the electric starter, electric

lights, and dimmable headlights. During World War I he built

airplane engines for the U.S. government, and afterward converted

the design for use in his new creation, the Lincoln.

Throughout, he demanded precision from himself and those

working for him. Once, for example, he complained to Alfred P.

Sloan that a lot of ball bearings that Sloan had sold him varied

from the required engineering tolerances and showed Sloan a

few misshapen bearings to prove the claim. “Even though you

make thousands,” Leland admonished Sloan, “the first and last

should be precisely the same.” Sloan took the lesson very seriously.

When he later led General Motors to the top of the industry,

he credited Leland with teaching him what mass production

was all about.



See also: CAD/CAM ; Assembly line ; Internal combustion engine .