M390 is considered to be in the "premium steels" category; whereas, *CPM-154/N690 are tagged in the "high-end steels" and *A2/D2 are "mid-range steels" categories... then, you go down to the *pot-metals, like 440C [<<
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The knife's *edge-retention, *corrosion-resistance, *toughness and *ease-of-sharpening are the 4 major criteria each is graded on.
Yes! I guess, similar to *FR, *THD, *SINAD, *IMD criteria.
View attachment 287632
This one is a quitie!
M390, ceramic-bearings, flipper, purple titanium handle, a liner-lock and a key-chain clip.
Notice that circled torx screw? I did too.
I have NO IDEA what purpose it serves.
Notice the inside of the liner locker that has been machine sanded? I did too.
I have NO IDEA what purpose that serves either.