When I cut the end of my finger off (just a tiny slice) I was trying to teach an almost deaf woman to sew. I think she heard me yell. Dr. wasn't in yet, had to call the cop who is also EMT. He said I was lucky. Didn't cut enough off to matter and too small to sew back on.
It was years ago and I still have a funny pointed finger.
Saleslady told me about a one inch tall plastic fence you can set on any ruler. It is stuck where you put it. But it has saved me.