Many years ago, I was building a desk and needed a large ogee edge detail for the top. Obviously a shaper job but I had no cutters that size.
Neither did any of the tool catalogs I had! What I did find were those big cutterheads with the removable knives. I ended up ordering one along with a set of custom ground knives.
At the time I had a Rockwell shaper with a 3/4" spindle. I had installed the optional 1" spindle cartridge but even so, this cutterhead looked so scary that I almost aborted the whole idea.
At about the middle of the cut there was a funny sound and I felt something like a subtle breeze blowing past my head. The machine started to vibrate but I was able to get it shut off. That's when I noticed that one of the knives was missing. I looked around but did not find it, then I noticed a small slot in the wall behind me.
To make a long story short, the cutter had gone completely through the wall of the building. I found it in the driveway about 20 feet away from the wall. Being young and foolish, I mounted the thing back up and finished making the cut. But not before building a massive shroud around the cutterhead!