How Does a Power Saw Work?

The Basics

A power saw is an electrical tool that is activated by an electrical switch. The tool runs off of standard 110-volt house current and a high-quality electrical saw can draw 20 amps of electrical current or more. This high amperage requirement allows for a powerful and clean cutting action of the circular saw blade.

When the switch of the saw is turned on, electricity flows to the electric motor, which spins at a high rate of speed and automatically engages a metal shaft which also spins at a high rate of speed. At the end of the shaft there is a circular saw blade with teeth that form a continuous circle around the outside of the flat, round piece of metal. If the teeth are sharp the spinning blade cuts through a piece of wood until the switch is released.

Once the switch is released the saw blade stops drawing power and the blade spins until into it runs out of inertia. If the power button to the saw is released, while the blade is engaged in a cut, the saw blade will immediately come to a halt. Only a blade that is not engaged in a cut will keep spinning after the power is shut off.

The Circular Action

The blade of a power circular saw cuts by spinning a sharp-toothed blade at a high rate of speed. The sharpness of the teeth along with the type of blade determines the type of cut that is made. There are many different type of blades for kinds of situations.

Some blades are meant for cross-cutting, while other blades might be meant for ripping the length of a board. There are even blades that are designed to cut and plane at the same time, while other blades are especially designed for different materials. For example, one might want to use a special blade to cut sheets of plastic.

Sometimes a circular saw can be used to make a partial cut. To do this, one might use a blade that makes an extra-wide cut (these are called Dado blades) and they will set the depth of the cut, so that it only goes part way through the piece of wood. In this way a circular saw can be used to make furniture, as well as the more conventional tasks of cutting the end off of a board.

Worm Drive

For most types of power saws, the shaft which holds the blade spins in the same direction as the electric motor that powers the saw. With a simple transfer of power the shaft spins in sync with the electric motor. In this type of saw there is a simple transfer of power from its electrical source to the mechanical work performed by the circular saw blade.

However, for a very powerful cutting device some carpenters use a worm-drive power saw, where the circular blade is driven by a belt that operates in much the same manner as the fan belt in your car. These innovative tools are powerful machines indeed and even though the saws weigh more than your average circular saw, their cutting power is much enhanced and always very smooth.

To use one of these tools is an experience very much similar to driving a high performance spots car. The saws do not bog down even when ripping through very dense wood. It is no wonder that many experienced carpenters opt for a worm-drive power saw despite the added expense at the time of purchase.