I don't remember if it was on this site or another but i had read somewhere "Never stick your finngur where you wouldn't stick your d***"

Also just something id like to add to the diagram that ken posted, that black line between the red/green is probably the WORST place to be if i was a betting man and had to bet which way a prop blade would go should it decided to leave the hub its gonna be somewhere n that black line 90% of the time...