I'll do the math

assuming a 3450 RPM table saw with a 10 inch 65 tooth rough cut blade

From a fixed point, 65 teeth @ 3450 RPM gives us 3738 teeth per second
passing a fixed point. Sawstop claims to be able to stop the blade in
5ms on a bad day, so that leaves us with 19 teeth passing over your
finger in the time it takes the blade to stop. Now that's assuming that
you're able to instantly insert your finger into the path of the blade.
You would have to be moving your finger at over 150 ft per second or 103
mph to make that happen. Since sawstop is assuming 1 ft per second or
..7mph, your finger will make it roughly 1.525 mm into the blade. Skin
varies in thickness from between .5mm on your eyelids to 4.5mm on your
hands and palms, so if the saw is able to do it's job in 5ms and you're
honestly just not paying attention and aren't doing something boneheaded
like trying to force the board through the blade, you should have a
scratch roughly 1.5mm deep. It'll bleed, but not for long.

Take this for what it's worth, it's just math. Math and reality often
don't play well together, but the sawstop theory is sound. BTW, I'm not
affiliated with sawstop, I'm just an engineer and number crunching is
about as wild and crazy as I get on a Friday night.


Jason
The place where you made your stand never mattered,
only that you were there... and still on your feet


Jim Northey wrote:
"Scott Lurndal" wrote in message
.. .
B A R R Y writes:
On 29 Sep 2006 14:50:33 -0700, "tomwalz"
wrote:

Have you ever ripped with a 3 or 5 HP cabinet saw and a real rip
blade? Your hand is typically moving rather quickly while performing
this operation.
And that's what push-sticks and feather boards are for.

FWIW, sans editorial comment, from this months Sawdust Shop newsletter:


Another SawStop Save

Table saw
accidents can happen at any time and to anybody. One of our customers
who purchased a SawStop table saw from us back in March recently made
contact
with the spinning blade with his fingers. The SawStop braking system
triggered,
stopped the blade, and he ended up with just a scratch.

This is our third customer save since we started selling the SawStop and
we
are glad to hear that it prevented a potentially tragic accident.

We are proud to be a dealer for the innovative SawStop table saw.

Ok I do not disagree with the safty aspect o the saw stop . What I do have
is a problem with the above statment ( if it's word for word from their
newsletter) . As I understand it , a blade with 1/8 " kerf give or take,
spinning at X amount of revolutions per minute stops in 0.0whatever seconds
and comes in contact with any body part can leave nothing more than a
scratch. It's to late in the day and I've had more than a few so I'm not
going to do the math on how many teeth will have contacted the flesh on that
body part . Anything 1/8th wide is not what I would consider just a scratch.
A minor cut I can understand but a scratch is what you do with a fingernail
or something you get when you **** off the cat.
Jim