I've used my Delta Unisaw as a hobbyist for 10 years and
never had a kickback--until yesterday.
I was ripping a piece of oak about 8 inches wide and 20
in. long. I was using a blade guard with integrated splitter
and anti-kickback pawls. I had a horizontal featherboard
holding the workpiece against the fence. The offcut was
about 1/4 in. wide. The rip cut was complete and I was
pushing the workpiece past the blade when I heard a loud
whap! and felt something hit me me hard just below
the belt. The offcut piece had been caught by the blade and
turned into an arrow. I was only bruised but I know it
could have been a lot worse.
Somehow the anti-kickback pawl was not properly engaging the
offcut piece. The pawl is easily deflected sideways and an
offcut piece only 1/4 in. wide can easily slip to either side
of the pawl, entirely escaping it's grip. The offcut piece must
have flopped around enough to get caught by the blade. The
workpiece between the blade and the fence remained
where it should be.
I'm not sure what to do to keep a thin offcut piece from
getting caught by the blade but I've learned two lessons:
1) Like the safety books say, keep your body out of the
plane of the blade. I usually do this, but "usually"
doesn't help when kickback happens.
2) Accidents can happen when you least expect it. Just
before I started the cut I thought "This cut is properly
set up--lots of safety here." I felt safe, but breaking
one safety rule is all it takes.