|Steve Gass, David Fanning, and David Fulmer (cofounders)|
SawStop is a table saw manufacturer headquartered in Tualatin, Oregon, USA. The company was founded in 1999 to sell table saws that feature a patented automatic braking system that stops the saw within milliseconds if its blade comes in contact with the operator's hand or other body part.
How it works
|“||Stopping the blade...would require a two-part process. First, [Gass] needed a brake that would work quickly enough when it came into contact with a woodworker's hand. Next, he had to design a triggering system that could differentiate between finger and wood. Given the speed of the blade, it would have to stop in about 1/100 of a second — or at about an eighth of an inch of rotation after making contact. Any further, and the cut would be so deep that the device would be useless. To stop the blade this quickly would require about 1,000 pounds of force to decelerate the blade in 10 milliseconds.||”|
SawStop's saws apply a small amount of electric voltage to the blade of the saw. The current through the blade is continuously monitored. If the saw detects a change in this current (as would occur if a hand or other body part came into contact with the blade) an automatic braking system is activated, forcing an aluminum brake block into the blade. The saw stops within five milliseconds, and angular momentum lowers the blade into the table. The operator suffers a small nick instead of an amputation or other more serious injury. The design takes advantage of the difference in "electrical conductivity" (similar to a GFI circuit) between wood and flesh.
According to SawStop, there are restrictions and limitations:
- 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 often damages one to two teeth on the blade.
Steve Gass, an amateur woodworker with a doctorate in physics who worked as a patent attorney, came up with the idea for SawStop's braking system in 1999. It took Gass two weeks to do the design, and a third week to build a prototype based on a "$200 secondhand table saw." After numerous tests using a hot dog as a finger substitute, in spring 2000, Gass conducted the first test with a real finger on himself: 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.
SawStop, at the time consisting of "three guys out of a barn in Wilsonville", demonstrated a prototype in August 2000, at the International Woodworking Machinery and Furniture Supply Fair, a trade show. A series of meetings followed, where in an attempt to license his invention, Gass "negotiated with major players such as Ryobi, Delta, Black & Decker, Emerson, and Craftsman"; he followed up on those negotiations with a February 2001 presentation to the Defense Research Industry (a trade group for attorneys representing the power-tool industry). That presentation immediately preceded one from Dan Lanier, Black & Decker's national coordinating counsel; Lanier's presentation gave Gass the impression he was unlikely to succeed in convincing major power tool manufacturers to license SawStop technology.
In July 2001, SawStop was awarded a safety commendation by the U.S. Consumer Product Safety Commission (CPSC) for "developing innovative safety technology for power saws intended to prevent finger amputations and other serious injuries." In 2002 Popular Science named SawStop's technology one of its "100 Best New Innovations."
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. According to Gass, when a typographical error in the contract had not been resolved after six months of effort by Gass to get Ryobi to sign the proposed deal, Gass gave up on the effort in mid-2002. Some subsequent licensing negotiations were deadlocked when the manufacturers insisted that Gass should "indemnify them against any lawsuit if SawStop malfunctioned", something Gass wouldn't agree to since he would not be manufacturing the saws."
The failure to license it to Ryobi or another manufacturer prompted SawStop to start its own company; 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."
Citing statistics that show 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 The number of finger or hand amputations in the US has more recently been estimated to be 4000 annually, costing more than $2 billion a year to treat victims.
In June 2006, the CPSC recommended that the U.S. government begin the rulemaking process that could result in mandatory safety standards for table saws.
SawStop has provoked opposition from the Power Tool Institute (PTI), which represents Black & Decker, Hilti, Hitachi Koki, Makita, Metabo, Bosch, Techtronic Industries and WMH Tool Group. In April 2008 they told Congress that SawStop's braking system is:
- 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, ranging from a minimum of 25 percent 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; 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." 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."
- Melba Newsome (July 2005). "He Took On the Whole Power-Tool Industry". Inc. Retrieved 2013-06-06.
- "CPSC Chairman Awards Safety Commendation to SawStop, LLC". Washington, DC: Consumer Product Safety Commission. July 20, 2001. Retrieved 2011-06-19.
- Jason Ford (10 July 2001). "SawStop makes for safer woodworking". The Engineer. Retrieved 2011-06-29.
- "FAQ". SawStop. Retrieved 2011-06-19.
- Charles J. Murray (September 3, 2006). "Man on a Mission". Design News. Retrieved 2011-06-19.
- "Requesting the Consumer Product Safety Commission To Initiate Rulemaking for Table Saws" (PDF). Petition. Consumer Product Safety Commission. April 15, 2003. Retrieved 2011-06-29.
- "HB0450". Illinois General Assembly. 2005. Retrieved 2011-06-19.
- Jeff Plungis (June 9, 2011). "Consumer Safety: A Fight Over Table Saws". Bloomberg Businessweek. Retrieved 2011-06-29.
- Jennifer C. Kerr (May 25, 2011). "New rules for table saws sought to cut amputations". Associated Press. Salon.com. Retrieved 2011-06-29.
- Susan M. Young (April 10, 2008). "The Power Tool Institute's Comments Opposing H.R. 4783" (PDF). House Committee on Ways and Means. Retrieved 2011-06-19.