What about the gray area?

This past week, I had a rather interesting conversation regarding copper strip. This particularly copper strip is wrapped around aluminum and the seam is tig-welded. Before being wrapped around the aluminum, the strip is cut to ensure a uniform edge. After looking at numerous breaks with the seam visible, this step in the process sent up red flags because anything that has to do with cutting must wear. The resulting conversation:

T: How do you know if the cutting tool is in good working condition?

S: Well, we know it is bad when we see a burr.

T: So you have good cuts and you have bad cuts. What about the gray area in between?

S: It is either good or it is bad.

Really?