Wood has always been one of man's most important resources. Directly and indirectly, in fact, it has been one of his basic necessities. For example, primitive man used wood to make fires and to make the clubs with which he could protect himself and hunt. His wooden hunting weapon brought meat to his fire and fur clothing for his body. Besides clothing himself with skins, he used them again with wood to make crude shelters. He made the shelters he didn't make from wood and skins by weaving three branches together.But it was not until thousands of years later that he learned to make wooden houses. During these years, he used wood for his tool handles and for his first machines, the lever and the wheel. Wood also provided his first means of transportation when he learned to make crafts, wagons, and ships.

Throughout history, man has perfected ways to bend, carve, smooth, polish, stain, and paint wood, as well as change its size, shape, and appearance to suit his needs and his ideas of beauty. One of the most widely used and oldest known machines for woodworking is the circular saw. Circular saws are defined as machines in which the working tool takes the form of a steel disc equipped with teeth on its periphery. This disc, usually known as the circular saw blade, is mounted on an arbour in the case of bench saws or on a spindle in portable saws, from which it derives a circular motion.

The various types of circular saws are grouped in the following categories:
- Ordinary table saws.
- Rip saws, including travelling carriage saws.
- Automatic edgers with one or more saw blades.
- Cross-cut saws.
- Firewood saws.
- Portable electric hand saws.

The preceding sections of this report primarily address the portable electric saw, which is widely used for cross-cutting and ripping sawing of wood.