Circular saw

Acircular sawor abuzz saw,is a power-sawusing a toothed orabrasive discorbladeto cut different materials using a rotary motion spinning around anarbor.Ahole sawandring sawalso use a rotary motion but are different from a circular saw.Circular sawsmay also be loosely used for the blade itself. Circular saws were invented in the late 18th century and were in common use insawmillsin the United States by the middle of the 19th century.

A circular saw is atoolfor cutting many materials such aswood,masonry,plastic,ormetaland may be hand-held or mounted to a machine. In woodworking the term "circular saw" refers specifically to the hand-held type and thetable sawandchop saware other common forms of circular saws. "Skilsaw" and "Skil saw" have become generic trademarks for conventional hand-held circular saws in the United States of America. Circular saw blades are specially designed for each particular material they are intended to cut and in cutting wood are specifically designed for makingrip-cuts,cross-cuts, or a combination of both. Circular saws are commonly powered by electricity, but may be powered by a gasoline engine or ahydraulic motorwhich allows it to be fastened to heavy equipment, eliminating the need for a separate energy source.^[1]

History

There is evidence for the prehistorical use of circular saws by people ofIndus Valley Civilizationduring the Bronze Age. The same was excavated from the archeological site ofLothal,Gujarat.^[2]^[3]

The modern-day circular saw was invented around the end of the 18th century as arip-sawto convert logs intolumberin sawmills and various claims have been made as to who invented it. Before the design was invented, logs were sawn by hand using apit sawor using powered saws in a sawmill using anup-and-downsaw with areciprocating motion.The rotary nature of the circular saw requires more power to operate but cuts faster because the teeth are in constant motion. The sound of the circular saw is different from the sound of an up-and-down saw and earned it the nicknamebuzz-saw.

Sawmills first used smaller diameter circular saws to resaw dimension lumber such aslathandwall studsand foredgingboards. As the technology advanced large diameter saw blades began to be used for thehead sawsand to cutclapboards.

Claims to the invention of the circular saw include:

A common claim is for a little-known sailmaker namedSamuel MillerofSouthampton,England who obtained a patent in 1777 for a saw windmill.^[4]^[5]However, the specification for this only mentions the form of the saw incidentally, indicating that it was probably not his invention.^{[original research?]}
Gervinus of Germany is often credited with inventing the circular saw in 1780.^[6]
Walter Taylorof Southampton had theblockmakingcontract forPortsmouth Dockyard.In about 1762, he built asaw millwhere he roughed out the blocks. This was replaced by another mill in 1781. Descriptions of his machinery there in the 1790s show that he had circular saws. Taylorpatentedtwo other improvements to blockmaking but not the circular saw.^[7]^[8]^[9]This suggests either that he did not invent it or that he published his invention without patenting it (which would mean it was no longer patentable).
Another claim is that it originated in the Netherlands in the sixteenth or seventeenth century.^[10]
The use of a large circular saw in a saw mill is said to have been invented in 1813 byTabitha Babbitt,aShakerinventor, after she noted the inefficiency of the traditionalsaw pitsused by the sawyers in her community and sought an improvement.^[11]^[5]^[12]This claim is now mostly discredited.^[13]^[14]
The Barringer, Manners and Wallis factory in Rock Valley,Mansfield,Nottinghamshire also claims to be the site of the invention.^{[citation needed]}

Process

Typically, the material to be cut is securely clamped or held in avise,and the saw is advanced slowly across it. In variants such as thetable saw,the saw is fixed and the material to be cut is slowly moved into the saw blade. As each tooth in the blade strikes the material, it makes a small chip.^[15]The teeth guide the chip out of the workpiece, preventing it from binding the blade.

Characteristics

Cutting is by teeth on the edge of a metal blade or by an abrasive wheel
The cut has narrowkerfand relatively smooth surface finish
Cuts are straight and relatively accurate
The saw usually leaves burrs on the cut edge of metal and plastic (which should then be addressed with sand paper)
Saw setting should be done geometrically^{[clarification needed]}

Types of circular saws

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

Abrasive saw
Biscuit joiner
Brushcutter
Carbide saws
Cold saw
Concrete saw
Flip over saws(the combination of a compound miter and table saw)
Miter saw(chop saw, cut-off saw)
Multi-tool (powertool)
Panel saw
Pendulum sawor swing saw
Radial arm saw
Sally saw
Swingblade sawmill
Table saw
Track sawor plunge saw

Sawmill blades

Portable sawmill circular saw blade about 60 cm (2.0 ft) diameter.

Originally, circular saws in mills had smaller blades and were used to resaw lumber after it passed through an "up and down" (muley or sash) saw leaving both vertical and circular saw marks on different sides of the same piece. These saws made it more efficient to cut small pieces such as lath. After 1813 or 1822 saw mills use large circular saws, up to 3 metres (9.8 ft) in diameter. Large saws demand more power than up-and-down saws and did not become practical for sawing timbers until they were powered by steam engines. They are either left or right-handed, depending on which side of the blade the plank falls away from.Benchingdetermines which hand the saw is. Saws of this size typically have ashear pinhole, off axis, that breaks if the saw is overloaded and allows the saw to spin free. The most common version is theITCO(insert tooth cut-off) which has replaceable teeth. Sawmill blades are also used as an alternative to a radial arm saw.

Cordwood saws

Allis-Chalmers Bwith a cordwood saw setup

Cordwood saws, also called buzz saws in some locales, use blade of a similar size to sawmills. Where a sawmill rips (cuts with the grain) a cordwood saw crosscuts (cuts across the grain). Cordwood saws can have a blade from 20 inches (510 mm) to more than 36 inches (910 mm) diameter depending on the power source and intended purpose. Cordwood saws are used to cut logs and slabs (sawmill waste) intofirewood.Thecubic meterandCord (unit)are common measurements of standing timber (by estimation) or rough logs. "Cordwood" means unsplit logs 4 feet (1.2 m) long. In the nineteenth and early twentieth centuries, farmers would supply householders in town with cordwood, which would then be re-sawn and split to a length and circumference suitable for woodburning heaters and ranges. Almost all these devices were designed to accept 16-inch (410 mm) sticks, conveniently a piece of cordwood cut into three equal lengths. Once a piece of cordwood had been re-sawn to three 16-inch pieces, it could easily be split to stovewood size with an ax.

Most cordwood saws consist of a frame, blade, mandrel, cradle, and power source. The cradle is a tilting or sliding guide that holds logs during the cutting process. Certain cordwood saws are run from a belt from a farm tractor power takeoff pulley. Others, mounted on a tractor's three-point hitch, connect to the rear power takeoff shaft. Self-powered models are equipped with small gasoline engines or even large electric motors as power sources. The mandrel is a shaft and set of bearings that support and transfer power to the blade. The frame is a structure that supports the cradle and blade at a convenient working height.

Cordwood saws were once very popular in rural America. They were used to cut smaller wood into firewood in an era when hand powered saws were the only other option. Logs too large for a cordwood saw were still cut by hand.Chainsaws^[16]have largely replaced cordwood saws for firewood preparation today. Still, some commercial firewood processors and others use cordwood saws to save wear and tear on their chainsaws. Most people consider cordwood saws unsafe and outdated technology.

Hand-held circular saws for wood

An unusually large hand-held circular saw for cutting timbers with a roughly 16 in (410 mm) blade.

In woodworking the term circular saw is most commonly used to refer to a hand-held,electriccircular saw designed for cutting wood, but may be used for cutting other materials with different blades. Circular saws can be either left or right-handed, depending on the side of the blade where the motor sits. A left-handed saw is typically easier to use if held in the right hand, and contrariwise for the right-handed saw, because the user does not need to lean across the saw to see the cutting line.

Blades for cutting wood are almost universallytungsten carbidetipped (TCT), but high-speed steel (HSS) blades are also available. The saw base can be adjusted for depth of cut and can tilt up to 45° and sometimes 50° in relation to the blade. Adjusting the depth of cut helps minimize kickback. Different diameter blades are matched to each saw and are available ranging from 14 to 61 centimetres (5.5–24.0 in).

Saws can have two different types of linkages between the motor and the blade. In the type known colloquially as asidewinder,the blade is mounted directly on themotor'sdriveshaft.In aworm-drivesaw, the blade is driven by a perpendicularly mounted motor usingworm gears,which give higher torque.

The worm-drive portable circular saw was invented in 1923 by Edmond Michel. In 1924 Michel formed a partnership with Joseph Sullivan, and together they started theMichel Electric Handsaw Company,with the sole purpose of manufacturing and marketing the saw invented by Michel. The company later renamed itselfSkilsaw Inc.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 EmmonsofPorter-Cableinvented the direct-drive sidewinder saw in 1928. Recently^[when?]smallercordlesscircular saws withrechargeable batterieshave become popular.

Cold saw for metal

Cold saw machines are circular saws that are used in many metal cutting operations. The saw blades used are quite large in diameter and operate at low rotational speeds, and linear feeds. There are three common types of blades used in circular saws; solid-tooth, segmental tooth, and the carbide inserted-tooth. The circular saw is typically fed into the workpiece horizontally, and as the saw advances into the material, it severs the material by producing narrow slots. The material is usually held in place during the cutting operation by means of a vise. The chips produced by cutting are carried away from the material by both the teeth of the blade as well as the coolant or other cutting fluid used.

Abrasive saws

Circular saw with a diamond blade for cutting asphalt and concrete.

The rotary motion of a circular saw lends itself to cutting hard materials like concrete, asphalt, metal, tile, brick, and stone with anabrasive sawsuch as atile saw.Diamond bladesandcut off wheelsare commonly used in these applications.

References

^"Power saw"(PDF).Archived fromthe original(PDF)on 2014-03-15.Retrieved2014-03-15.
^Raj Pruthi (2004). Prehistory and Harappan Civilization. APH Publishing. p. 185.ISBN 978-81-7648-581-4.
^Rebecca Kraft Rector (15 July 2016). The Early River Valley Civilizations. The Rosen Publishing Group, Inc. p. 45.ISBN 978-1-4994-6328-6.
^English Patent Specification no. 1152 (1777)
^^a ^bInventors website
^Haskins, Sonya (2007).The Homeschooler's Book of Lists.Bethany House. p. 191.ISBN 9780764204432.
^Carolyn C. Cooper, "The Portsmouth System of Manufacture"Technology and Culture25(2) (1984), 182–195
^C. Singeret al.,History of TechnologyIV (1958), 437
^Ball, Norman (1975). "Circular Saws and the History of Technology".Bulletin of the Association for Preservation Technology.7(3): 79–89.doi:10.2307/1493506.JSTOR 1493506.
^Ball, 'Circular Saws' quoting M. Powis Bale,Woodworking Machinery. Its Rise, Progress and Construction.
^Curtis, John O. (1973). "The Introduction of the Circular Saw in the Early 19th Century".Bulletin of the Association for Preservation Technology.5(2): 162–189.doi:10.2307/1493401.JSTOR 1493401.
^"Wood News Online - No. 11, April 2006".www.highlandwoodworking.com.
^Miller, M. Stephen (20 October 2018).Inspired Innovations: A Celebration of Shaker Ingenuity.UPNE.ISBN 9781584658504– via Google Books.
^"RG - Workshop: History of the Circular Saw".ronin-group.org.Archived fromthe originalon 2019-01-11.Retrieved2015-09-21.
^Todd, Robert; Allen, Dell; Alting Leo (1994).Manufacturing Processes Reference Guide.Industrial Press. p. 28.
^Chainsaws – Chainsaw History

External links

History of the portable circular saw
Hand held power saws – Has a section on handling kickback
Circular Saw Safety Procedures Archived2010-05-31 at theWayback Machine
NIOSH Power Tools Sound Pressure and Vibrations Database Archived2016-06-30 at theWayback Machine

[1] "Power saw"(PDF).Archived fromthe original(PDF)on 2014-03-15.Retrieved2014-03-15.

[2] Raj Pruthi (2004). Prehistory and Harappan Civilization. APH Publishing. p. 185.ISBN 978-81-7648-581-4.

[3] Rebecca Kraft Rector (15 July 2016). The Early River Valley Civilizations. The Rosen Publishing Group, Inc. p. 45.ISBN 978-1-4994-6328-6.

[4] English Patent Specification no. 1152 (1777)

[auto-5] Inventors website

[6] Haskins, Sonya (2007).The Homeschooler's Book of Lists.Bethany House. p. 191.ISBN 9780764204432.

[7] Carolyn C. Cooper, "The Portsmouth System of Manufacture"Technology and Culture25(2) (1984), 182–195

[8] C. Singeret al.,History of TechnologyIV (1958), 437

[9] Ball, Norman (1975). "Circular Saws and the History of Technology".Bulletin of the Association for Preservation Technology.7(3): 79–89.doi:10.2307/1493506.JSTOR 1493506.

[10] Ball, 'Circular Saws' quoting M. Powis Bale,Woodworking Machinery. Its Rise, Progress and Construction.

[11] Curtis, John O. (1973). "The Introduction of the Circular Saw in the Early 19th Century".Bulletin of the Association for Preservation Technology.5(2): 162–189.doi:10.2307/1493401.JSTOR 1493401.

[12] "Wood News Online - No. 11, April 2006".www.highlandwoodworking.com.

[13] Miller, M. Stephen (20 October 2018).Inspired Innovations: A Celebration of Shaker Ingenuity.UPNE.ISBN 9781584658504– via Google Books.

[14] "RG - Workshop: History of the Circular Saw".ronin-group.org.Archived fromthe originalon 2019-01-11.Retrieved2015-09-21.

[15] Todd, Robert; Allen, Dell; Alting Leo (1994).Manufacturing Processes Reference Guide.Industrial Press. p. 28.

[16] Chainsaws – Chainsaw History

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