How the edge should look like

Technical drawing: Deburring corners like this

Technical drawing: Rounded corners or better like this

The rounded edges also minimize the development of nicks.

not like this! Technical drawing: sharp edges - so non

and also not like this! Technical drawing: sharp edges like a mushroom - so non
The mushrooming shown in the last picture forms a sharp edge. Mushrooming occurs on soft Show combat weapon when they are used for fencing.