Circular saws are a cutting tool favoured by carpenters, joiners, builders and other professionals. The round, revolving blades, usually serrated, quickly slice through wood, making smooth rip cuts (parallel to the grain) and crosscutting (perpendicular to the grain). They are also used to cut cement board, plastic and panelling, while specialist blades can be fitted for metal, masonry and other hard substances.
Circular saws are more energy-efficient than conventional saws because their cutting motion is continuous. On traditional reciprocating saws, by contrast, the cutting strokes alternate with return strokes.
First devised in the 18th century, manual circular saws quickly became a popular choice for cutting wood and were standard equipment in sawmills. Nowadays, most circular saws are electrical power tools, noted for their versatility, ease of use and considerable cutting power. Hydraulic models are also available, and some saws have additional features such as electric brakes or laser guides.
Both built-in desk-mounted and handheld designs are available, with the latter also known as electric hand saws. The motor used in the latter is typically 1-2 horsepower, with the blade wheel spinning at around 5000 revolutions per minute (rpm). Operators can adjust the blade depth and angle of the cut (from 90° to 45°, for example).
Electric models typically feature sturdy insulated casing and either a fixed or retractable blade guard, but caution and proper training are essential for safe use. Users should wear personal protective equipment (PPE) such as visors and gloves when operating power tools.