Table saws are among the most dangerous tools on a construction site or in a home workshop, and the US Consumer Product Safety Commission (CPSC) has spent years working toward a rule that would require every table saw sold in the country to include active injury mitigation, the technology best known as flesh detection. When skin touches the spinning blade, the saw detects the contact and stops the blade within milliseconds. The concept sounds simple, but the comments Harbor Freight filed with the CPSC in early 2024 explain why the technology is still not on every saw sold. Harbor Freight built its reputation on value-priced lines such as the Hercules family, and the Hercules sliding miter saw shows how far budget tools have come, yet the company’s submission makes clear that adding flesh detection involves far more than bolting a new part onto an existing design.
What the Proposed Rule Would Require
The proposed rulemaking targets every table saw sold in the United States, regardless of brand or price point. Under the draft standard, each saw would need a system that detects skin contact and either stops the blade or retracts it below the table surface quickly enough to prevent serious injury. The CPSC has estimated that table saws cause tens of thousands of emergency room visits each year, and a significant share of those injuries involve amputations or permanent hand damage. The agency has weighed injury data and compliance costs for more than a decade.
The proposal drew comments from both sides. Tool makers, industry groups, and safety advocates submitted arguments about cost, feasibility, and testing procedures. Harbor Freight’s filing does not claim the technology is unnecessary. Instead, it argues that the rule as written cannot be met by most manufacturers on the proposed timeline. The company pointed to the CPSC’s own recall work as evidence of how safety problems surface in real products, and the Harbor Freight cordless drill recall teaches a clear lesson about power tool safety: a defect found after thousands of units reach shelves costs far more than one prevented during design.
- Every new table saw sold in the country would need active injury mitigation or an equivalent system.
- The system must stop or retract the blade within a fraction of a second after skin contact.
- Saws would need to pass a standardized contact test before they could be sold.
- Compliance would apply to imported saws as well as domestic production.
The Hardware Problem: Sensing Modules and Circuit Boards
Flesh detection depends on two pieces of technology working together. A sensing module sits near the blade and reads electrical changes in the area around it. A programmed circuit board interprets those signals and fires the brake mechanism. In Harbor Freight’s words, the board must be programmed so the module functions consistently with the proposed rule, and that programming is where the trouble starts. The company states that it knows of only one manufacturer making a sensing module, and even that supplier says it does not make or program the circuit board required to meet the standard.
SawStop and the Power Tool Institute (PTI) members that worked on the technology treat the programming of the sensing module as trade secret information. According to Harbor Freight, they have not shared that know-how with other table saw manufacturers and have not agreed to license it, based on the company’s own inquiries and on evidence presented by others. None of the overseas manufacturers that build table saws for Harbor Freight know how to program the software, and Harbor Freight’s own engineering team lacks the experience needed to instruct them.
The gap matters because mechanical protection is not a substitute. Blade guards and riving knives reduce risk but cannot stop a blade that touches skin, and even those mechanical parts have reliability problems of their own. A miter saw blade guard recall covered by Family Handyman shows how a guard can fail in the field, which is one reason regulators keep pushing for electronic solutions that do not depend on the user keeping a shield in place.
Why the Firmware Is the Hard Part
The sensing module is only part of the system. The firmware on the circuit board must distinguish skin from the materials the saw is meant to cut. Wood, plywood, and composites all have electrical properties that shift with moisture content, so the detection logic has to stay accurate across a wide range of conditions without false trips that stop the blade during normal cuts.
Calibration and False Trips
A system that trips too often is worse than no system, because users learn to distrust it or disable it. Getting the balance right took SawStop years of testing, and that accumulated experience is exactly the know-how that Harbor Freight says is locked inside patents and trade secrets rather than available to the wider industry.
| Safety approach | How it works | Main limitation |
|---|---|---|
| Blade guard | Covers the blade from above | Users remove it; does not stop contact |
| Riving knife | Prevents kickback | No protection against direct blade contact |
| Flesh detection with brake | Detects skin contact and stops the blade in milliseconds | Patented, premium price, restricted firmware know-how |
| Retracting blade system | Drops the blade below the table on contact | Complex mechanism with the same sensing requirements |
Patents, Trade Secrets, and Fair Licensing
The central dispute in Harbor Freight’s filing is not whether the technology works. It is whether other companies can legally and practically build it. The proposed rule would effectively require SawStop-style safety technology, but unexpired patents cover the core methods. Without a license, competitors cannot build a compliant saw at all, and without the firmware know-how, even a patent license would not be enough to produce a working product.
Harbor Freight asks the CPSC to mandate a Fair, Reasonable, and Non-Discriminatory (FRAND) license covering both the unexpired patents and the implementation know-how. FRAND terms are common in telecommunications and electronics, where standard-essential patents are licensed to any willing manufacturer at reasonable rates. Applying the same framework to table saws would mean any maker could pay a fair royalty and build a compliant saw instead of being locked out of the market.
Licensing fights over safety-critical technology are not unique to power tools. In heavy equipment, certification regimes shape which machines reach a job site, and marine and offshore construction equipment used for coastal protection and harbor works faces its own version of the problem when proprietary control systems sit behind a single supplier. The table saw debate is a sharper version of the same tension between proprietary know-how and public safety goals.
What a FRAND Mandate Would Change
- A royalty rate that is fair and reasonable rather than set by the patent holder alone.
- Access for all table saw manufacturers on the same terms, with no discrimination between large and small brands.
- Coverage of implementation know-how, not just patents, so licensees can actually build and program compliant systems.
- A defined timeline so manufacturers can engineer, test, and certify saws before the rule takes effect.
Development Timelines Set the Baseline
Harbor Freight makes a timing argument that is hard to dismiss. SawStop spent many years developing its flesh detection system before the first saw reached the market. The PTI effort, a collaborative program involving multiple table saw competitors and a substantial team of engineers, also took years. Harbor Freight argues that those timelines are the baseline for what any other vendor would need to develop and implement the patented technology from scratch.
The technology does work in the real world. Hands-on reviews of flesh detection saws show the system performing reliably in daily use, and a SawStop jobsite saw review covering table size and fence quality shows that safety features can coexist with good ergonomics. But a working product and a licensable, manufacturable design are different things, and that difference sits at the heart of the timeline problem.
Years, Not Months
Even with a license in hand, a manufacturer would need to source modules, write and validate firmware, build test rigs, run third-party certification, and redesign the saw around the detection system. Each step carries its own delays. Harbor Freight’s point is that the proposed rule assumes a level of industry readiness that does not exist yet.
What This Means for Shops and Buyers
The rulemaking affects anyone who buys a table saw, not just the companies that make them. If the rule passes with a workable licensing scheme, flesh detection will eventually become standard equipment on new saws across price points. If it stalls, or if the licensing questions stay unresolved, the technology will remain a premium feature on higher-end saws and the safety gap will stay in the budget segment where most injuries happen.
Portable saws show the tradeoff clearly. Performance testing of a portable table saw with flesh detection highlights the balance between table size, build quality, and safety hardware, and the price premium is real. Buyers comparing contractor saws to jobsite models have to decide whether the added cost of active injury mitigation fits their budget and their risk profile.
Questions to Ask Before Buying
- Does the saw include active injury mitigation, or only mechanical guards?
- How much does a replacement brake cartridge cost, and how many activations fit the budget?
- Is the detection system covered by the warranty, and what happens after a real activation?
- If the rule takes effect later, will the current saw still be acceptable on job sites?
Practical Steps While the Rulemaking Proceeds
Regulation moves slowly, and workshops cannot wait for it. The practical safety measures available today cost little and address the two biggest table saw hazards: blade contact and kickback. They are not a replacement for flesh detection, but they close a meaningful part of the gap.
- Keep the blade guard and riving knife installed and adjusted for every cut that allows them.
- Use push sticks and featherboards so hands never enter the blade zone.
- Set blade height so the blade rises only slightly above the workpiece.
- Train every user on the saw’s controls and on how to respond to kickback.
- Inspect guards, switches, and fences before each session.
Budget-conscious buyers do not have to choose between safety and price. Compact table saw safety practices built around guard discipline and workholding deliver most of the benefit without the premium hardware, and for many shops that is the right starting point while the industry resolves the licensing question.