SawStop is an American table saw manufacturer headquartered in Tualatin, Oregon. The company was founded in 2000 to manufacture table saws that feature a patented automatic braking system that stops the blade upon contact with skin or flesh.
Table saws are "by far the most dangerous woodworking tool."[1] The operator holds the wood, rather than the saw, making it easy to guide both fingers and wood into the saw. In the United States roughly 10 table saw finger amputations occur every day.[2][3][4]
SawStop is safer because of its automatic braking feature, but it is still a dangerous machine and must be used with great care. For example, woodworker Rex Krueger did not lose his finger, however, he had a painful experience requiring treatment in a medical emergency department.[5]
SawStop was designed to prevent serious injury to a person who had already made contact with a saw blade spinning at 4000 rotations per minute(RPM). Because the safety feature is reactive instead of preventative, it would have to do two things almost instantly and very reliably:
Determine that contact had been made with the saw blade.
Stop the saw blade.
Both of these problems were difficult to solve, because the saw blade is spinning very fast.[2]
How it works
According to the manufacturer's website, the saw blade stops in less than five milliseconds,[6] while angular momentum retracts the blade into the table. The operator suffers a minor instead of serious injury.[7] The design takes advantage of the difference in conductance and capacitance between wood and flesh.[8]
An oscillator generates a 12-volt, 200-kilohertz (kHz) pulsed electrical signal, which is applied to a small plate on one side of the blade. The signal is transferred to the blade by capacitive coupling. A plate on the other side of the blade picks up the signal and sends it to a threshold detector.
Replaceable braking cartridges
Cartridge and 10-inch, 36-tooth saw blade taken from a Saw Stop table saw after activation of safety mechanism
Saw braking cartridge after activation. Notice the aluminum frame has been crushed as a result of impact by moving saw blade, and the spring stretched.
If a human contacts the blade, the signal will fall below the threshold. After a signal loss lasting for 25 microseconds (μs), the detector fires. A tooth on a 10-inch circular blade rotating at 4000 RPM will stay in contact with a fingertip for about 100 μs. The 200-kHz signal will have up to 10 pulses during that time, and should be able to detect contact with just one tooth.[9] When the brake activates, a spring pushes an aluminum block into the blade. The block is normally held away from the blade by a wire, but during braking an electric current instantly melts the wire, similar to a fuse blowing.
Even with this safety features, the SawStop is still a dangerous machine, and must be used with great care.
Limitations
According to SawStop, the system has restrictions and limitations:[10]
The braking system must be deactivated when cutting very green or wet timber.
Non-conductive blades or blades with non-conductive hubs or teeth cannot be used.
The braking system is designed to work with kerfs from 3/32″ to 3/16″; using thinner or thicker kerfs limits the saw's ability to stop the blade after accidental contact, likely resulting in more serious injury.
It is impractical to retrofit into existing table saws.
Activating the braking system usually damages the blade, and requires the replacement of a braking cartridge.
Drawings from SawStop patent applications
Left side of table saw
Right side of table saw, with table not shown
SawStop patent applications
History
Invention (1999)
Steve Gass, a patent attorney and amateur woodworker with a doctorate in physics,[2] came up with the idea for SawStop's braking system in 1999.[11] It took Gass two weeks to complete the design, and a third week to build a prototype based on a "$200 secondhand table saw."[2] After numerous tests using a hot dog as a finger-analog, in spring 2000, Gass conducted the first test with a real human finger: he applied Novocain to his left ring finger, and after two false starts, he placed his finger into the teeth of a whirring saw blade. The blade stopped as designed, and although it "hurt like the dickens and bled a lot," his finger remained intact.
Prototype and founding of company (2000)
SawStop, at the time consisting of "three guys out of a barn in Wilsonville", demonstrated a prototype in August 2000[2] at the International Woodworking Machinery and Furniture Supply Fair trade show.[11] A series of meetings followed, in which Gass "negotiated with major players such as Ryobi, Delta, Black & Decker, Emerson, and Craftsman" in an attempt to license his invention; he followed those negotiations with a February 2001 presentation to the Defense Research Industry, a trade group for attorneys representing the power-tool industry.[2]
Gass was immediately followed by a presentation from Dan Lanier, Black & Decker's national coordinating counsel. Lanier expressed concern that if any manufacture licensed the safety feature, all others would be forced to do likewise, or risk litigation following injuries with their products.[2]
After hearing Lanier's presentation, Gass thought he was unlikely to succeed in convincing major power tool manufacturers to license SawStop technology.[2]
In July 2001, SawStop was awarded a safety commendation by the US Consumer Product Safety Commission (CPSC) for "developing innovative safety technology for power saws intended to prevent finger amputations and other serious injuries."[7] In 2002 Popular Science named SawStop's technology one of its "100 Best New Innovations."[12]
Attempt to license (2002)
In January 2002, SawStop appeared to come close to a licensing agreement with Ryobi, who agreed to terms that involved no up-front fee and a 3% royalty based on the wholesale price of all saws sold with SawStop's technology; the royalty would grow to 8% if most of the industry also licensed the technology.[2] According to Gass, when a typographical error in the contract had not been resolved after six months of negotiations, Gass gave up on the effort in mid-2002.[13] Subsequent licensing negotiations were deadlocked when the manufacturers insisted that Gass should "indemnify them against any lawsuit if SawStop malfunctioned"; Gass refused because he would not be manufacturing the saws.[2]
Start of manufacturing (2004)
The company's failure to license the technology to any manufacturer prompted SawStop to become a manufacturing company itself; over two years later, the company's first saw was produced by a Taiwanese manufacturing plant in November 2004. By 2005, SawStop had grown to "eight people out of a two-story barn Gass built himself."[2]
Citing statistics showing accidents in the US with table and bench saws resulted in 3000 amputations annually of one or more fingers, SawStop's technology inspired Representative Kevin Joyce to propose the Illinois General Assembly's 2005 Electrical Saw Safety Act.[14] The number of finger or hand amputations in the US has more recently been estimated to be 4000 annually,[15] costing more than $2 billion a year to treat victims.[2][3]
In June 2006, the CPSC recommended that the US government begin the rulemaking process that could result in mandatory safety standards for table saws[citation needed].
Product liability litigation against Ryobi and other saw manufacturers (2006)
Gass served as an expert trial witness in 2006 when Carlos Osorio sued Ryobi for injuries sustained when he was injured using a Ryobi table saw. Osorio claimed the saw could have been made safer if it had used Gass's invention. Gass also worked with plaintiffs on other table saw lawsuits.[16]
Opposition from trade group (2008)
SawStop has provoked opposition from the Power Tool Institute (PTI),[15] which represents Black & Decker, Hilti, Hitachi Koki, Makita, Metabo, Bosch, Techtronic Industries (owner of Ryobi), and Walter Meier Holdings (WMH Tool Group, owner of JET and Powermatic[17]). In April 2008, they told Congress that SawStop's braking system is:[18]
dangerous because it requires the user to come in contact with the blade before activating;
unproven, particularly in terms of durability;
prone to false trips caused by commonly available wet and green wood;
potentially vulnerable to latent damage that cannot be inspected and may cause a hazard;
costly to the user because once activated, saw blade and cartridge must be replaced; and
significantly more expensive, costing at least 25 percent more than a standard saw and ranging upwards depending on saw type
The PTI objects to the licensing necessary due to the "more than 50 patents" related to SawStop's braking system;[18] they say such costs "would destroy the market for the cheapest, most popular saws, adding $100 or more to the price of consumer models that typically sell for less than $200."[15] In response, their members developed "new plastic guards to shield table saw users from the dangers of a spinning blade" and began selling models with that feature in 2007; as of May 2011, PTI says "its member companies have received no reports of injuries on [the 750,000] table saws with the new guard design."[3]
The Power Tool Institute is also concerned that SawStop patented technology might force other manufacturers to pay unreasonable royalties to SawStop. The Institute also suggests that SawStop users have become less careful, because they have a "sense of security" in the ability of SawStop to protect them, a behavior called risk compensation.[19]
Competition appears (2015)
Bosch began manufacturing a competing product, the Bosch REAXX Jobsite Table Saw, which also has finger-saving ability, but using a different technology. Bosch's new REAXX contractor's table saw appeared at the World of Concrete trade show in Las Vegas in February 2015.[20] The Bosch saw retracts the blade below the table, but unlike SawStop, it does not stop or damage the blade.
Pro Tool Reviews published an article comparing the SawStop Jobsite Table Saw with the Bosch REAXX Jobsite Table Saw. They found both saws to be extremely well designed and built, and having many features desirable to contractors. They also found the SawStop made two minor scratches on a finger before stopping, and the Bosch safety saw made four minor scratches. Both saws seem able to save fingers.[21]
Patent litigation (2016)
In September 2016, Judge Thomas B. Pender made an initial determination that the new Bosch design infringes on patents 7,895,927 and 8,011,279 held by SawStop, but does not infringe on two other SawStop patents, 7,225,712 and 7,600,455.[22][23] In February 2017, the ruling entered a 60-day review period, giving attorneys time to comment before it would become final.[24]
In a separate legal action, Bosch attempted to have the SawStop patents invalidated. On March 31, 2017, the Patent Trial and Appeal Board denied Bosch the institution of Inter Partes Review (IPR), thereby leaving the SawStop patents in force.[25]
New ownership by TTS Holding (2017)
Since July 2017, SawStop has been owned by TTS Tooltechnic Systems Holding AG (Germany), which also owns Festool. Consequently, Festool offers saws with SawStop technology.[26]
Patent expiration (2021)
The SawStop patents began to expire in September 2021.[27] SawStop holds around 100 patents, though many of them are continuations of the early SawStop patents. The continuation patents may expire later than the "parent" patent due to patent office delays. Some SawStop continuation patents expire as late as May 2026.[28]
Intent to release patent (2023-2024)
On October 18, 2023 the U.S. Consumer Product Safety Commission (CPSC) voted to publish a Supplemental Notice of Proposed Rulemaking (SNPR)[29] to address the Active Injury Mitigation (AIM) and what patents SawStop holds that may be effected.
In February 2024, in response to proposed rulemaking regarding table saw safety by the CPSC, SawStop committed to dedicate U.S. Patent 9,724,840 to the public upon the rule's effective date.[30] In response to the SawStop announcement a Commisioner of the CPSC released a statement praising SawStop's gift to the public.[31]
Litigation is expected to follow from power tool manufacturers on how to best implement the AIM technology or outright fight the requirement of said technologies. If passed this mandate will improve the safety of all table saws, but will in turn increase the price of table saws.
A circular saw or a buzz saw, is a power-saw using a toothed or abrasive disc or blade to cut different materials using a rotary motion spinning around an arbor. A hole saw and ring saw also use a rotary motion but are different from a circular saw. Circular saws may also be loosely used for the blade itself. Circular saws were invented in the late 18th century and were in common use in sawmills in the United States by the middle of the 19th century.
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 air are also commonly used. Tools directly driven by animal power are not generally considered power tools. Power tools can produce large amounts of particulates, including ultrafine particles. Airborne particulate matter is a Group 1 carcinogen.
A chainsaw is a portable handheld power saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar.
A table saw is a woodworking tool, consisting of a circular saw blade, mounted on an arbor, that is driven by an electric motor. The drive mechanism is mounted below a table that provides support for the material, usually wood, being cut, with the blade protruding up through the table into the material.
A safety razor is a shaving implement with a protective device positioned between the edge of the blade and the skin. The initial purpose of these protective devices was to reduce the level of skill needed for injury-free shaving, thereby reducing the reliance on professional barbers.
The United States Consumer Product Safety Commission is an independent agency of the United States government. The CPSC seeks to promote the safety of consumer products by addressing "unreasonable risks" of injury ; developing uniform safety standards ; and conducting research into product-related illness and injury. In part due to its small size, the CPSC attempts to coordinate with outside parties—including companies and consumer advocates—to leverage resources and expertise to achieve outcomes that advance consumer safety. The agency was created in 1972 through the Consumer Product Safety Act. The agency reports to Congress and the President; it is not part of any other department or agency in the federal government. The CPSC has five commissioners, who are nominated by the president and confirmed by the Senate for staggered seven-year terms. Historically, the commission was often run by three commissioners or fewer. Since 2009, however, the agency has generally been led by five commissioners, one of whom serves as chairman. The commissioners set policy for the CPSC. The CPSC is headquartered in Bethesda, Maryland.
Dremel is a multinational brand of power tools, focusing on home improvement and hobby applications. Dremel is known primarily for its rotary tools, such as the Dremel 3000, 4000 and 8200 series, which are similar to the pneumatic die grinders used in the metalworking industry by tool or moldmakers. Dremel later expanded its product range and now produces butane tools, benchtop and hand-held saws and oscillating tools. The company was purchased by Robert Bosch GmbH in 1993, and is now a division of the Robert Bosch Tool Corporation.
A miter saw or mitre saw is a saw used to make accurate crosscuts and miters in a workpiece by positioning a mounted blade onto a board. A miter saw in its earliest form was composed of a back saw in a miter box, but in modern implementation consists of a powered circular saw that can be positioned at a variety of angles and lowered onto a board positioned against a backstop called the fence.
A rare-earth magnet is a strong permanent magnet made from alloys of rare-earth elements. Developed in the 1970s and 1980s, rare-earth magnets are the strongest type of permanent magnets made, producing significantly stronger magnetic fields than other types such as ferrite or alnico magnets. The magnetic field typically produced by rare-earth magnets can exceed 1.2 teslas, whereas ferrite or ceramic magnets typically exhibit fields of 0.5 to 1 tesla.
SKILSAW Power Tools is a manufacturer of circular saw-cutting technology serving the professional construction market. Since 2017, SKILSAW's headquarters has been located in Naperville, Illinois.
Festool is a brand of high-end power tools from Germany. Festool Group GmbH & Co. KG is based in Wendlingen and is a subsidiary of the TTS Tooltechnic Systems holding company. It is known for its system-based approach to power tools and its focus on dust extractors.
Toy safety is the practice of ensuring that toys, especially those made for children, are safe, usually through the application of set safety standards. In many countries, commercial toys must be able to pass safety tests in order to be sold. In the U.S., some toys must meet national standards, while other toys may not have to meet a defined safety standard. In countries where standards exist, they exist in order to prevent accidents, but there have still been some high-profile product recalls after such problems have occurred. The danger is often not due to faulty design; usage and chance both play a role in injury and death incidents as well.
A fence is a part of many woodworking tools; it is typically used to guide or secure a workpiece while it is being sawn, planed, routed or marked. Fences play an important role for both accuracy and safety. Fences are usually straight and vertical, and made from metal, wood or plastic.
Techtronic Industries Company Limited is a Hong Kong–based multinational company that designs, produces, and markets power tools, outdoor power equipment, hand tools, and floor care appliances. It pioneered cordless power tools powered by lithium-ion rechargeable batteries.
Pamela B. Gilbert is an American lawyer and has been a partner of the law firm Cuneo Gilbert & LaDuca, LLP since 2003, where she heads the firm's lobbying practice. Gilbert is a noted consumer rights advocate who has testified before Congress over fifty times and made dozens of appearances in the national print and electronic media. Gilbert leads the Committee to Support Antitrust laws (COSAL), an organization supportive of antitrust legislation.
Vornado is an American fan and home appliance brand based in Andover, Kansas, United States. The current incarnation of the company was founded in 1989, two years after the death of Ralph K. Odor (1895–1987), who founded the firm in the 1930s with Ottis A. Sutton in Wichita. The name of the company is a combination of Vortex and Tornado.
Systainers are modular inter-stacking plastic containers used for transporting power tools. Boxes from different manufacturers are compatible and can be stacked and clipped together. A design using four joining clips was introduced by Festool Tooltechnic in 1993. In 2010 the T-Loc variant was introduced using a rotating handle for connecting and locking of containers, in combination with redesigned feet.
An electric motor brake is a safety feature incorporated into many modern power tools, such as circular saws, drills, and miter saws. Many manufacturers implement this feature into tools specifically with a spinning blade or cutter.
A plunge saw or plunge-cut saw is a type of hand-held circular saw which differs from a regular circular saw in that it can plunge into the material to a predetermined depth during the cut. In other words, the depth-of-cut is not fixed and often can be adjusted to be just slightly over the thickness of the board being cut. This property also allows a plunge saw to cut shallow grooves into the workpiece, if necessary. Compared to traditional hand-held circular saws, plunge saws are said to increase operator safety, as well as allowing for reduced splintering and tear-out. Plunge saws are an essential power tool for joiners, carpenters, kitchen fitters and anyone who works with laminates, insulation or needs to make lots of cuts in small work pieces.
Makita Auto-Start Wireless System, Festool Autostart (2018‒) and Bosch Wireless Auto-Start (2024‒) are Bluetooth-based systems for remotely starting industrial vacuum cleaners from power tools. Several power tools, cordless battery packs, and industrial vacuum cleaners ship with wireless connectivity, mostly using Bluetooth Low Energy to communicate, but as of 2024 the systems remained incompatible between different brands.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
Cartridge and 10-inch, 36-tooth saw blade taken from a Saw Stop table saw after activation of safety mechanism
Saw braking cartridge after activation. Notice the aluminum frame has been crushed as a result of impact by moving saw blade, and the spring stretched.
