[Snip horrific circular saw story]
I have been cautious of circular saws ever since.
I worked in a factory for 5 years and a wood machinist there used to trim his nails on his circular saw!
One day, I watched him risk a horrible death. There was lots of sawdust and debris lying around on the ground below his circular saw bench and it would have been very easy for him to slip on it. He needed some rectangular pallets but all we had was a pile of square ones twice the size he needed. He decided to cut them in half.
He took the guard off his saw and wound the blade up until it was sticking out from the saw bench just more than the thickness of a pallet. He started the saw and was shoving a pallet through and the saw was almost stalling from the strain of making such a deep cut. The machinist was a big strong man, about 6' 3" tall and he was using all his strength to force the pallet through.
I could see exactly what could happen ... the last of the pallet is suddenly cut through and shoots forward exposing the spinning blade. the machinist's foot slips on the sawdust and he falls forward onto the exposed sawblade. It cuts through the front of his face, his throat or his ribcage, he dies in front of me ...
I couldn't watch, so I turned to walk away. I heard the saw blade suddenly rev back up to full speed, there was the clunk of a pallet falling to the floor and a yelp of fear from behind me. I turned and saw the machinist standing there shaking.
He grinned nervously and said
"Oops - that was a bit close!"