Only took once for me and that was with an OS 60 and a master airscrew prop, with in a mounth I had my first sulavan starter. I still have the scar to this day. The prop kicked back and nailed my left pointer finger. It opened the side of my finger up like the gill on the side of a fish right to the bone. I was the only one home and the hospital was over 20 miles away. So I washed it off, got out the thick CA and glued it shut. Didn't really hurt much until I hit the CA with Zap Kicker. Then it got a whole lotta hot, LOL I think I screamed for 15 minutes straight. The CA sealed the cut up nicely and it took about 6 month for the nerves to grow back together.
Everythime I see some one starting a engine by hand, It still makes me think of my mishap and I grab the starter and left them use it.
NEDYOB