A jigsaw is a saw which uses a reciprocating blade to cut irregular

curve In mathematics, a curve (also called a curved line in older texts) is an object similar to a line, but that does not have to be straight. Intuitively, a curve may be thought of as the trace left by a moving point. This is the definition that ...

s, such as

stencil Stencilling produces an image or pattern on a surface, by applying pigment to a surface through an intermediate object, with designed holes in the intermediate object, to create a pattern or image on a surface, by allowing the pigment to reach ...

ed designs, in

wood Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...

metal A metal (from ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, e ...

, or other materials. Jigsaws first emerged in the 19th century and employed a

treadle A treadle (from oe, tredan, "to tread") is a mechanism operated with a pedal for converting reciprocating motion into rotating motion. Along with cranks, treadmills, and treadwheels, treadles allow human and animal machine power in the a ...

to operate the blade, which was thin and under tension, being secured at both ends to an oscillating frame. This kind of saw is now usually called called a scroll saw. The modern portable jigsaw, with a rigid blade secured at one end, was introduced in 1947 by Scintilla AG (later acquired by Bosch), A jigsaw

power tool A power tool is a tool that is actuated by an additional power source and mechanism other than the solely manual labor used with hand tools. The most common types of power tools use electric motors. Internal combustion engines and compressed ...

is made up of an

electric motor An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate f ...

and a

reciprocating saw A reciprocating saw is a type of machine-powered saw in which the cutting action is achieved through a push-and-pull ("reciprocating") motion of the blade. The original trade name Sawzall is often used in the United States, where Milwaukee Elec ...

blade A blade is the portion of a tool, weapon, or machine with an edge that is designed to puncture, chop, slice or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are to be used on. Histor ...

. Jigsaws with sole plates that have a beveling function can cut angles typically up to 45 degrees relative to the normal vertical stroke to make

miter joint A mitre joint (often miter in American English) is a joint made by cutting each of two parts to be joined, across the main surface, usually at a 45° angle, to form a corner, usually to form a 90° angle, though it can comprise any angle greater ...

s. Portable jigsaws have historically been mains-powered, but are increasingly being displaced by battery-powered models.

History

In 1946 Albert Kaufmann, an

engineer Engineers, as practitioners of engineering, are professionals who Invention, invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considerin ...

of Scintilla AG company in

Solothurn Solothurn ( , ; french: Soleure ; it, Soletta ; rm, ) is a town, a municipality, and the capital of the canton of Solothurn in Switzerland. It is located in the north-west of Switzerland on the banks of the Aare and on the foot of the Weissens ...

, Switzerland, replaced the needle on his wife's

sewing machine A sewing machine is a machine used to sew fabric and materials together with Thread (yarn), thread. Sewing machines were invented during the first Industrial Revolution to decrease the amount of manual sewing work performed in clothing companies. ...

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. An important innovation by Scintilla-Bosch in 1966 was the "pendulum action", where the blade tilts forward in the upward (cutting) stroke, and back for the down-stroke, so the blade runs cooler and cuts faster. The degree of "pendulum action" was adjustable to suit the material being cut. Such a mechanism introduces additional purchase and maintenance costs, and manufacture of such models may have ceased in recent years. Many modern jigsaws have an adjustment for tilting the blade tip forward, but at a static, fixed angle, claiming similar benefits.

Blades

A Jigsaw works by attaching a blade accessory to the tool. There are various types of blades in the market. Older jigsaws require a blade to be screwed into the tool. But since Bosch introduced the first tool-free blade change system, most manufacturers now offer a similar setup allowing a quick & tool-free blade change. There are T-shank blades and U-shank blades available in the accessory market. T-Shank blades are the industry-standard professional interface that provides a longer life and a tighter fit from the blade to the tool. Tooth design is important for the performance of a blade. The tooth spacing, tooth shape, and cutting angle are important in providing speed, cleanliness of cuts, and optimal performance. A side set and ground tooth is designed for clean and fast cuts in wood and plastics. Wavy set and milled teeth will cut most metals as well as plastics. A side set and milled tooth works with fast and rougher cuts in wood and plastics. A ground and taper-ground tooth is for precise, fine and clean cuts in wood. There is also reduced-kerf carbide and diamond grit edges for fast cutting in hard materials.

Blade material

Different blade materials are used for different applications to improve blade life and cutting performance. High-carbon steel (HCS) is used for softer materials such as wood, laminated particle board, and plastics due to its flexibility. High-speed steel (HSS) withstands higher temperatures and can cut many types of metals.

Bi-Metal Bimetal refers to an object that is composed of two separate metals joined together. Instead of being a mixture of two or more metals, like alloys, bimetallic objects consist of layers of different metals. Trimetal and tetrametal refer to objects co ...

(BIM) blades contain a combination of high-carbon steel and high-speed steel. The combination creates a strong and flexible material that can be used for demanding applications where there is a risk of breakage or when extreme flexibility and versatility is required. Bi-Metal blades have longer lifespans and prolonged job performance compared to other types of blades.

Tungsten carbide Tungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into ...

(TC) blades have the strength to cut through abrasive metals such as reinforced plastics, fiberglass, cement board, stainless steel, tile, glass, cast iron, and brick. Diamond-grit blades are extremely versatile, as they can cut rough materials such as hard porcelain tile, granite, slate, marble, and other stones due to their finely milled particles. This makes their uses similar to carbide blades, although diamond-grit blades typically last longer.

Controllability

Control is an issue with jigsaws; the blades are small and weak, with the lower end entirely unsupported. Good cut control requires the presence of blade rollers, which keep the blade aligned just above the sole plate. In addition, heavy-cast sole plate saws are somewhat better than pressed steel for sawing line control. To guide a jigsaw on curved cut, it must be steered (turned) and not forced to move sideways. The use of sharp blades is important as well to get high quality cuts.

References

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