The other day one of my coworkers showed up to work with a new handy little tool. He had purchased a handheld jig which he could clamp his knife into. The jig allowed him to more precisely sharpen his knife by utilizing calibrated holes on either side of the knife jig and one of several different grit hones. He successfully sharpened his knife with it to a small angle and proved that he could shave his arm hair with it since it was so sharp. I told him that the only problem with sharpening it to such a small degree was that the edge would be damaged much more easily even by just using it since the edge doesn't have as much geometric structure below it to provide strength. I told him that his knife would be much more usable and reliable with a higher angle.

I should note that that was just my opinion and I could be completely wrong, so please let me know if you believe I was incorrect.

This instance at work got me thinking about the different angles of a blade and it's sharpness. I read on one of the forums where someone defined sharpness as the attribute of a blade where the two sides of an edge meet at an infinitesimally small width line. If this definition is accurate, which logically it sounds, then it could be said that one could attain an equally sharp blade at 45 degrees as opposed to 10 degrees (just numbers from the air). But a 45 degree edge would be more resilient since it has more supporting material below it.

I should state that I don't believe this to be the case because of experience, however, I wanted to state the contradiction I see so people will better understand my question. Then again maybe it is true and I am some genius that has uncovered a truth that will make humanity better. Nobel Prize anyone J/K. I guess my question is why do we choose one edge angle over another? It will probably be answered real quick by someone telling me that the definition I read, however elegantly correct it sounds, is incorrect. I appreciate any insight.

Jeremy