Jigsaw (power tool)
A jigsaw is a tool used for cutting arbitrary curves, such as stenciled designs or other custom shapes, into a piece of wood, metal, or other material. It can be used in a more artistic fashion than other saws, which typically cut in straight lines only. In this way, it is similar to the rasp and the chisel. Although a jigsaw can be used to cut arbitrary patterns, making a straight cut freehand is difficult even with a guide.
Traditional jigsaws are hand saws, consisting of a handle attached to a small, thin blade. The first jigsaw puzzles were made using this kind of unpowered saw. More modern jigsaws are power tools, made up of an electric motor and a reciprocating saw blade.
A jigsaw with a bevel function on the sole plate allows cutting angles of typically up to 45 degrees relative to the normal vertical stroke for cutting miter joints.
In the past, what are now usually called scroll saws were often referred to as jigsaws.
A (power) jigsaw may also be referred to, by some manufacturers, as a "bayonet saw" or sabre saw.
In 1946 Albert Kaufmann, an engineer of Scintilla AG company in Solothurn, Switzerland, replaced the needle on his wife's sewing machine with a saw blade. In 1947, after development of Kaufmann's invention, Scintilla started producing jigsaws under name "Lesto jigsaw". In 1954 Scintilla was acquired by Bosch and in 1964 the name "Lesto" was replaced with Bosch. In 1966 Bosch added the pendulum action to the blade movement and in 1989 it added the tool-less blade replacement device. This is the history of the Bosch jigsaw. Numerous other manufacturers had been mass-producing jigsaws decades before Kaufmann repurposed his wife's sewing machine.
There are 2 main types of blade fitting in use. The older type uses a screw to hold the blade; the newer type slots in.
A wide variety of blade types are used, including:
- various numbers of TPI (Teeth Per Inch)
- blade edge for cutting soft materials
- cranked blades to overcome the setback of the blade and allow flush cutting
- thin blades to allow tighter curves to be cut
- push stroke cutting blades to avoid damage to the top surface. These are problematic to use
Control is an issue with jigsaws. The blades are small, weak and entirely unsupported at the lower end. Good cut control requires the presence of blade rollers, which keep the blade aligned just above the sole plate. Heavy cast sole plate saws are somewhat better than pressed steel for sawing line control too. To guide a jigsaw on curved cut, it must be steered (turned) and not forced to move sideways. The usage of sharp blades is important also to get high quality cuts.
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