You’ve probably heard about the Sawstop table saw — the one that instantly brakes itself to prevent its spinning blade from cutting flesh. I bought one last month, and finally got it all set up. It saws like a charm! I couldn’t be happier with it’s performance. In particular, dust collection is very good, the hand cranks are a dream (smooth and repeatable), and ripping or cross cutting a 2×6 board had no discernable reduction in RPM. The cuts were smoother than what I get from my surface planer, and that was with the stock blade that came with the saw. I’ve used a number of other table saws, and the Sawstop was relatively easy to make all the adjustments, and is very repeatable.
As for the safety features, I’ve haven’t put the brake to the test. Like the air bag in your car, the Sawstop system includes an extensive startup and continuous self test while idle and running. And like your air bag it’s very costly to “test.” You get only one emergency stop per blade and brake. Besides $70 for a new brake, it’s another $50-100 for a new blade. It’s pretty high tech. The brake is a special aluminum block and electronic assembly with a fusible (i.e. burnable) wire holding the spring loaded brake block assembly in position. When the electronics “fires” after detecting contact with human flesh, the fusible wire is burned through by a high electric current “pulse”. When the wire burns through, the spring loaded aluminum block is shoved into the spinning blade. The blade cuts deeply into the block, and the block absorbs the considerable momentum energy of the blade, arbor, belt and motor. The result is that the blade and block get hot enough near the teeth of the blade to unsolder or weaken the teeth on the blade. In short the blade is ruined 50% of the time according to one web site I found that had tested the unit. Once the emergency brake has been fired you need to replace the whole brake assembly (like the air bag), which includes the brake, spring, retaining fusible wire, firing electronics including capacitor, and brake frame assembly. Replacement only takes a couple of minutes. Despite the cost, it is still better than paying for a new finger. Two friends have lost 2.5 fingers collectively from table saws. And both were experienced woodworkers.
A hot dog proxy for a finger gets only a nick when pushed into a turning saw blade
The Sawstop has other safety features, too. The riving knife and blade guard are both first rate, much better than others I’ve used (the guard is small, low profile, and narrow, making narrow rips easier with the guard in place). Both are very easy to swap in and out. Lastly, the start/stop switch is a large paddle, perfectly placed for shutting off with a twist of the knee while you hold that thin strip tight against the fence, to prevent the smooth cut from being ruined while you fumble for the off button. So, so far, it is great.
I’ve never had a close call on a saw yet, but as I age, I know the extra insurance of having the Sawstop system might save a finger or two.