Jpfalt

During the early days of electrification, Westinghouse and Edison duked it out. Westinghouse went with AC from Nicola Tesla and Edison went with DC. As a part of the early marketing Edison Electric went around doing demos where they electrocuted dogs with AC to show how unsafe AC electricity was. This stuff was done for marketing to make a profit on electricity. The SawStop hoopla smacks of the same sort of dismay to make a profit.

After reading the CPSC thing that SawStop proposed, I think some attention should go to where SawStop doesn't work. I'd preface this by saying that according to SawStop, there ar about 3500 tablesaw injuries per year. According to University of Florida there ate approximately 50,000 injuries per year from tablesaws and chop type miter saws. This indicates that table saws are relatively minor players in the sawing tool injury population.

In reading the SawStop CPSC recommendation, the conditions excluded from coverage by SawStop include cutting wood with a moisture content above 50% and cutting aluminum, which is conductive. I would asume that this also would include graphite, conductive plastics and anything with aluminum foil content. For these the CPSC recommendation includes a bypass switch to disarm the SawStop.

From the SawStop website, the workings of the sensing device requires that the circuitry see a drop in electrical resistance, a rise in electrical resistance and a second drop in electrical resistance before the safety device triggers. This correponds to one saw tooth entering the finger, the saw tooth exiting the finger and then a second saw tooth entering the finger. How fine a blade would it take for the SawStop to be unable to distinguish between teeth and just keep going?

Then, if the wood I happen to be cutting is green, has a damp spot, has an inconveniently placed staple or nail, the device triggers and I've trashed a saw blade and a stop cartridge. How often am I likely to use the bypass switch?

So who wants to start in on an open source design for safety project to come up with something outside the SawStop patents that can be implemented or retrofitted without the licensing fees.

PREVENT THE SENSELESS SLAUGHTER OF INNOCENT HOT DOGS FOR PROFIT!!!

I saw something years ago about doing something similar without having to make up a blade. The idea was built around using the same laminated construction, but was made to fit standard bench chisles as blades.