On the first video clip @ 7 minutes into it........NEVER grind up on a grinding wheel. What he was going, he may have very well done it that way for years, and has just been lucky. All it takes is a fraction of a second to cause a major disaster, and by that I bean bodily harm.
I fuckkin hate seeing video's like that, someone has never seen something like that work, but then does something to imitate grinding a punch like that.
If he would happen to pull back on the punch, the wheel flips the punch down and runs the other end right through his hand. I've ran small bench grinders to large surface grinders. You never ever grind a part going into the part above centerline like he is showing. You want to be below centerline on the downstroke.
Anyone that has ever ran a surface grinder for any length of time at all and is proficient at it knows you always start on the right if the wheel has a CW rotation. That way a wheel cannot climb on top of a part. The same practice goes all of the way down to a bench grinder or pedestal grinder.
All it would take is one minute piece of the wheel missing on the backside that he didn't see to catch the punch.
