mitch
~ Elite 1000 Member ~
- Joined
- Jul 23, 2007
- Messages
- 2,636
Yesterday I started cutting on a knife frame and was noticing that while the metal did not seem inordinately hard, the cuts were rough- even jagged- on the surface. This could be seen under the microscope and was very obvious to my fingertip whenever i brushed away a chip. The point felt like it was holding up ok, but after awhile it seemed to drag and I swapped it out for a fresh sharp graver. Usually one notices a dull/chipped point when it fails to bite cleanly into the metal at the start of a cut. This graver was still fine in that respect, but felt rough as it was cutting lines.
This morning I took a closer look at these two graver points and noticed that apparently the hard surface of the steel was wearing the edges of the cutting face, but allowing the point to remain reasonably, functionally, intact. Since it would be difficult for me to photograph a graver point, I made a wooden mock-up to illustrate this phenomenon.
A couple years ago I worked on a knife that had been aggressively buffed to a mirror finish and had similar cutting characteristics (I did not notice any weird graver point wear at the time). I assume that what happens is the metal becomes overheated and is effectively case-hardened in the process. However, the knife I'm working on now had a nice wipe or brush finish, so perhaps the maker buffed it heavily before final fine grit polishing?
Note: The gravers were the one's Chris DeCamillis sells (used to sell?) for cutting stainless, plain old 90° squares, sharpened with 15° heel & 54° face.
This morning I took a closer look at these two graver points and noticed that apparently the hard surface of the steel was wearing the edges of the cutting face, but allowing the point to remain reasonably, functionally, intact. Since it would be difficult for me to photograph a graver point, I made a wooden mock-up to illustrate this phenomenon.
A couple years ago I worked on a knife that had been aggressively buffed to a mirror finish and had similar cutting characteristics (I did not notice any weird graver point wear at the time). I assume that what happens is the metal becomes overheated and is effectively case-hardened in the process. However, the knife I'm working on now had a nice wipe or brush finish, so perhaps the maker buffed it heavily before final fine grit polishing?
Note: The gravers were the one's Chris DeCamillis sells (used to sell?) for cutting stainless, plain old 90° squares, sharpened with 15° heel & 54° face.
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