Machines that Shape our World
From airplane parts to shopping carts, from computer chips to paper clips, our modern consumer culture is driven by the mass production of interchangeable parts.
The tiny steel screws that hold together your digital camera can be replaced with any other screw of the same size and type, made anywhere in the world. Ultimately, all of this interchangeability is made possible by machine tools: the power-driven machines that make parts to the most precise standards.
Interchangeable Parts: parts made to such tolerances that they can be freely substituted for one another and still be fully functional.
Machine Tools and Mass Production
At the Robbins & Lawrence Armory--in the building that now houses the American Precision Museum--a new system of manufacturing came of age.
In the 18th century, manufacturing had begun to move from cottage and shop into factories. Work was divided among laborers, but parts were still mostly made by hand. Then in the early 19th century, mechanics began to develop powered machines capable of producing wooden and metal parts quickly and accurately, hour after hour, with great precision.
Most of these early machine tools were produced by firearms manufacturers. Before there were machine tools, even guns built by the finest gunsmiths were not uniform. The parts for each weapon fitted only that weapon, and a gun that failed in the field became entirely useless until it could be repaired by a skilled gunsmith. Governments and arms makers recognized a solution to this problem: interchangeable parts.
The concept of interchangeable parts and the accuracy of new machine tools made possible a new mode of manufacturing. The "American System" would quickly spread across industries as well as oceans, creating a revolution in the production of consumer goods. In the 1840s and '50s, the armory in Windsor was at the head of this movement.
What is a Machine Tool?
A machine tool cuts metal or some other material to a predetermined shape, using some source of power other than muscle, and generally using a rigidly held and automatically controlled cutting tool. The machine tool increases speed, accuracy, and consistency in the metal shaping process.
Methods of Shaping Metal
The machine tools have traditionally cut metal in the following ways:
- Drilling or Boring
- Planing and Shaping
- Stamping, Punching, Pressing
- Sawing or Shearing
All of these methods can be performed by hand, but the machine tool can perform them more quickly and more uniformly, with less physical labor on the part of the worker. Today there are also new methods of shaping metal: laser beam machining, ultrasonic machining, chemical machining, and others. Each of these methods reduces hand labor and improves the accuracy of the work.
Machine Tools Today
Most of the early machine tools featured at the American Precision Museum were designed to shape metal parts. Today, machine tools shape many other materials, but ultimately all mass-produced goods depend upon metal-cutting machine tools. Either they contain precisely made metal parts or they are made by machines that are constructed of precisely made metal parts. In either case, their uniformity and low cost depend upon machine tools.
Today, machines controlled by computers function automatically, performing operations and changing tools according to numerically coded instructions. Machining today requires new skills, such as computer programming. But it also still requires the machinist to understand relationships, procedures and tolerances. The machinist must also have the craftsman's ability to conceive a product and develop a method to create that product.
From the beginning, machine tools have transferred skill from the hands of the worker to the machine, but the source of that skill has always been the human mind. Machine tools save physical labor and increase productivity, but they do not eliminate the need for intellect. They shape our world by providing an ever-expanding array of products and opportunities. They also demand of us a higher and higher level of education and technical understanding if we wish to stay at the cutting edge.
This exhibition created in 2006 was made possible through the generous support of Haas Automation Inc. and Hypertherm.