In article ,
Ernie Jurick wrote:
...
Yeah, if the blade is moving at 4000rpm and the reaction time is 5
milliseconds, all those sharp little teeth make a full revolution+.

4000rpm = 66.7 revolutions/second.
5ms = .005 second

66.7 x .005 = .3 revolutions.

Still very unpleasant - but not a full revolution.

It's a lot easier, cheaper and less painful to be careful. :-)

Of course - but even careful folks can have accidents.
--
--henry schaffer