Power saw

Saw

A crosscut hand saw about 620 mm (24 inches) long
Classification	Cutting
Types	Hand saw Back saw Bow saw Circular saw Reciprocating saw Bandsaw
Related	Milling cutter

A saw is a tool consisting of a tough blade, wire, or chain with a hard toothed edge. It is used to cut through material, very often wood. The cut is made by placing the toothed edge against the material and moving it forcefully forth and less forcefully back or continuously forward. This force may be applied by hand, or powered by steam, water, electricity or other power source. An abrasive saw has a powered circular blade designed to cut through metal.

Saws were at first serrated materials such as flint, obsidian, sea shells and shark teeth.

In ancient Egypt, open (unframed) saws made of copper are documented as early as the Early Dynastic Period, circa 3,100–2,686 BC. Many copper saws were found in tomb No. 3471 dating to the reign of Djer in the 31st century BC. Saws have been used for cutting a variety of materials, including people (see Death by sawing). Models of saws have been found in many contexts throughout Egyptian history. Particularly useful are tomb wall illustrations of carpenters at work that show sizes and the use of different types. Egyptian saws were at first serrated, hardened copper which cut on both pull and push strokes. As the saw developed, teeth were raked to cut only on the pull stroke and set with the teeth projecting only on one side, rather than in the modern fashion with an alternating set. Saws were also made of bronze and later iron. In the Iron Age, frame saws were developed holding the thin blades in tension. The earliest known sawmill is the Roman Hierapolis sawmill from the third century AD and was for sawing stone.