Kind of funny actually, back in the old Navy, in the days of wooden ships and iron men, when you went through boot camp one of the things you were issued was a Camp King folding knife. When you arrived aboard a ship, the first the the Boatswain would do is take you down to the Shipfitter's shack and stick the first half inch of the blade of your knife in a vice and snap it off. It was then up to you to smooth it down properly.
This was to prevent you from stabbing yourself while working on lines, and of course the added benefit of not being able to stab others helped.
Here is how the end of a purpose designed blade would look.
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The phone company uses knives similar in nature, what is called a "modified Sheepsfoot" blade with no real point and a thick hard back to be able to pound on it with a chipping hammer.