Comment by Someone1234
8 months ago
Competitor's versions of this don't destroy the blade. The reason competition no longer exist is because SawStop sued based on the limb detection, not the blade repositioning tech.
Expect better than SawStop to appear when able, and this issue to go away.
I'm actually kind of surprised that any implementation destroyed the blade. Like I don't actually care that the blade is moving, I care where the blade is moving. It seems like a trigger to yank the blade under the table would be the easier and more obvious way to do it.
A few-milliseconds yank covering up to a couple inches of blade height feels like a harder engineering problem than "trigger brakes already right near the blade to grab the shit out of the blade"
So we're somewhat lucky from an engineering standpoint. Because the blade is circular the only interval of time that really matters is from detection to first movement away. Because it triggers on touch the difference between getting sawed and not is millimeters. The time from first movement to full retraction only needs to be fast on human scale time in case the person's hand is still moving into the blade. Name brand SawStop is actually fairly slow on the retraction because it uses the blade's momentum to drive it and that's plenty of speed.
However, the blade-preserving system puts the explosive between the table and the pivot that's already there for retracting the blade. The full explosion force is there to force the blade down and it ends up being faster than the SawStop. Which while cool the SawStop was already fast enough so it's all the same.
So I don't know, I guess to me I'm surprised that the solution we jumped to first was a brake when the action of moving it out of the way takes far far less energy. It's only the energy to move the weight of the blade and bar down at the requisite speed, instead of needing to absorb the full energy of the spinning blade.
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I have had two brake activations in as many weeks, one on a dado stack (don’t ask). Neither destroyed the blade. Both blades will be back in service within a week.
Just putting out there: the popular idea that blades are always trash after an activation is not true.
That said, cheap big box store blades without carbide teeth will die a horrible death.
Carbide teeth are actually the part that gets destroyed on SawStop activations. Carbide is very brittle, so the sudden stop fractures it.
Yes, and they are consumable and replaceable by design, which goes to my point: the blade is not irreparably destroyed by the activation.
The missing teeth need to be replaced and the plate needs to be re-checked for runout, but most carbide-toothed blades are repairable.
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