On Fri, 08 Jan 2010 16:26:33 GMT, (Doug Miller)
wrote:

In article , "Leon" wrote:

"Puckdropper" puckdropper(at)yahoo(dot)com wrote in message
.. .



You've also got to get a new blade, too. I'm curious if the SawStop
technology would be effective enough if it would fire and just drop the
blade totally in to the saw rather than jamming it in to a piece of
metal. I realize there's no possibility of a second stage, where if
contact is still being made it could then stop the blade.

I'd rather have my fingers.

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.

IIRC, the original sawstop concept just jammed the blade; the
mechanism to drop it down was added a little later. I suspect these
are redundant mechanisms, each can do the job on its own, but both
together achieve the sort of reliability you would need in something
that's guaranteed to generate a lawsuit if it doesn't work.

My $.02

Paul F.