Circular saw

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Invented in England in 1780, the circular saw (also less-commonly known as the 'buzz saw' in the USA) is a metal disc or blade with saw teeth on the edge as well as the machine that causes the disk to spin. It is a tool for cutting wood or other materials and may be hand-held or table-mounted.

While today they are almost exclusively powered by electricity, larger ones, such as those in "saw mills", were traditionally powered by water turning a large wheel.

Most of these saws are designed to cut wood but may be equipped with blades designed to cut masonry, plastics or metal although there are purpose-made circular saws specially designed for particular materials.

In addition to hand-held circular saws, different saws that use circular saw blades include:

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Hand-held circular saws

Image:DeWalt circular saw.jpeg The term circular saw is most commonly used to refer to a hand-held electric circular saw designed for cutting wood, which may be used less optimally for cutting other materials with the exchange of specific blades. Circular saws can be either left or right handed, depending on which side of the blade the motor sits.

The saw can be designed for the blade to mount directly to the motor's driveshaft (known coloquially as a sidewinder), or be driven indirectly by a perpendicularly-mounted motor via worm gears, garnering considerably higher torque (Worm-drive saws).

The worm-drive portable circular saw was invented in 1924 by the Michel Electric Handsaw Company which renamed itself Skilsaw Inc., today a subsidiary of Robert Bosch GmbH. Portable circular saws are often still called Skilsaws or Skil saws. Its successor is still sold by Skil as the model 77. To get around the Skil patents, Art Emmons of Porter-Cable invented the direct-drive sidewinder saw in 1928. Recently smaller cordless circular saws with rechargeable batteries have become popular.

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Sawmill blades

Saw mills use very large circular saws, up to nine feet (3.6 meters) in diameter. They are either left or right handed, depending on which side of the blade the plank falls away from. Benching determines which hand the saw is. Saws of this size typically have a shear pin hole, off axis, that breaks if the saw is overloaded and allows the saw to spin free. The most common version is the ITCO (insert tooth cut-off) which has replaceable teeth.

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