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Tom Bender
08-23-2022, 7:12 AM
How about a similar setup for a band saw, a router, etc?

How about for a lawn mower?

BTW does the Saw Stop brake damage the motor? It surely is not built for instant stops.

Thomas Wilson
08-23-2022, 8:39 AM
How about a similar setup for a band saw, a router, etc?

How about for a lawn mower?

BTW does the Saw Stop brake damage the motor? It surely is not built for instant stops.

A clutch disengages the motor from the arbor. The deceleration forces on the blade and arbor drive also cause a latch to release so the blade and arbor disappear below the table. When qualifying modified brake cartridge design, thousands of actuations are performed on actual Sawstops. Apparently they survive.

SawStop reportedly has a band saw brake design. No public announcement about taking it to market. A lawnmower or router would be hard.

Steve Demuth
08-23-2022, 10:55 AM
There is blade stop tech for bandsaws used in the meat cutting industry. It requires the operator to wear gloves, and have their body "wired" via something like a ground strap. I think the trick is that they isolate the operator's body electrically, so contact can be detected, rather than as with Sawstop, isolating the blade. Obviously, with meat cutting, you can't have the thing trigger on conductive contact alone, since everything they cut is conductive. Overall, I'm guessing the bladestop system along adds more cost to a saw than most woodworkers pay for their entire saw. You can look up Scott Bladestop on the net to see details. I've also seen some tech that uses video based detection, although I don't think that has actually made any headway, given the success of the Bladestop solution.

I think a true SawStop like approach is very challenging with a bandsaw. Isolating the blade is much more difficult, and the amount of rotating mass you have to stop is much greater, since you can't stop the blade independently of the wheels. Sawstop decouples the blade from the motor mass when triggered to avoid having to stop that mass instantly, and the angular momentum of, say, a pair of 18" bandsaw blades is much greater than that of a motor rotor.

Ben Schmidt
08-23-2022, 11:12 AM
A router shouldn't be too hard. No need for the bit to drop below the table like with a blade, just stop the motor with a brake.

Richard Coers
08-23-2022, 12:59 PM
A router shouldn't be too hard. No need for the bit to drop below the table like with a blade, just stop the motor with a brake.
A router would be pretty tough. On the table saw you have a 10" diameter to grab, a router maybe 3/8". A table saw at 3450 rpm and a router 22,000 rpm. On a table saw a large arbor, on a router maybe 1/4" shank. Table saw has a lot of cast iron mass, a router is thin aluminum castings holding the bearings. Slamming the brakes on a router could actually pop it out of your hands. Heck of a challenge in my mind!

Steve Demuth
08-23-2022, 2:12 PM
I agree, for a handheld router. Also worth noting that the size and mass of the capture mechanism on a Sawstop is not insignificant. Handheld routers are pretty much just a motor with handles, and adding all the mechanism for stopping would make them considerably more unwieldy in both size and weight. A mounted router might be doable, though.

The tools where I would want it most are the bandsaw (acknowledging the challenges there), and the jointer. A jointer should be possible to stop, although I have doubts about a mechanism to actually drop the head the way Sawstop does the 10" blade, without rigidity of the head mounting suffering.

Jason Evans
08-23-2022, 3:55 PM
Great ideas here.

Another thing I’d like to see is some kind of sawstop type device to stop me from spending too much time staring at my computer or phone when I should be getting back to work.

Ben Schmidt
08-24-2022, 6:25 AM
A router would be pretty tough. On the table saw you have a 10" diameter to grab, a router maybe 3/8". A table saw at 3450 rpm and a router 22,000 rpm. On a table saw a large arbor, on a router maybe 1/4" shank. Table saw has a lot of cast iron mass, a router is thin aluminum castings holding the bearings. Slamming the brakes on a router could actually pop it out of your hands. Heck of a challenge in my mind!

Sorry should have specified, a router TABLE. Handheld would be very difficult, agreed.