Leon wrote:
"Doug Miller" wrote in message
...
In article , "Leon"
wrote:

Think about that for a sec, if the blade simply fell below the
surface and
continued to spin,,,, do you think a blade that is spinning against
a finger
and moving down 1-3 inches would cut you?

No, I don't.

Remember that the lower the blade is, the farther the cutting edge
is from the
front of the saw -- hence as the blade drops, it also moves away
from your fingers horizontally as well as vertically.

I think it would be imperative
that the blade stop spinning and perhaps not drop below the surface
as an alternative.

I don't think I agree. Watch -- carefully -- the slow-motion video at
sawstop.com, the one titled "How it Works". Pause it at 0:20 and step
forward
a frame at a time, watching as the blade contacts a finger. It
appears that
only one or two teeth actually touch it before the blade begins to
drop. Note also the manufacturer's statement that the blade stops in 5
msec. A 40-tooth blade at 3450 rpm is moving 38.33 teeth per second, or
26
msec per
tooth.


I have not seen the video lately but will take your word for it. Still, I
think I would trust a blade that actually stops over one
that moves out of the way.

But how fast can you stop it?

A 10" blade (~3' in circumfrence) rotating at 3450 rpm is moving the outer
edge at roughly 120 MPH. You ain't gonna stop anything moving that fast in
mere milliseconds without ripping something all to shreds and perhaps
destroying all life on the planet.