Why is carbon steel easier to sharpen?

Jan 7, 2007
"Can be," "can be...." coulda, woulda, shoulda, dude. I was keeping it simple. I stand by what I posted.


Go nuts---tech the guy to death with jargon....

Perpetuating misinformation helps no one. Just my 2 cents.
Dec 20, 2007
The blades on my Swiss Army knives are stainless steel and are very easy to sharpen, take a fine edge. We need to be careful not to get carried away with broad generalizations.


Knifemaker / Craftsman / Service Provider
Apr 28, 2012
I am projecting what in my head using a visualize analogy - hopefully it's useful to explain conceptual or leastly :rolleyes: entertaining...

raw materials: rubber, hard plastic(P) + very hard metal(M) cubes with 3mm length/side.

target object1 (B1): 10mm long x 3.4mm thick square stick just rubber (R)
B2: R with 1 P cube on the center of stick
B3: R with 1 M cube on the center of stick
cutter1: Knife - can cut rubber stick 30mm/s, P 2mm/s, M 0/s
cutter2: Laser - can cut rubber stick 1000mm/s, P 40mm/s, M 3mm/s

objective: Cut each B1-B3 into 2 detached even size triangle shape sticks in 1 second/ea. So the cutter will cuts fast when cutting rubber, slow down for non-rubber but skip to make sure reach the end of the rubber bar w/i 1 second.


B1 - K & L = success

B2 - K = failed because 2 cut sticks still attach together, partial join at the P cube.
L = success

B3 - K = failed
L = barely failed since it cut most of the M cube but a tiny dangling metal uncut, which shielded the rubber from laser. So there still rubber connecting the 2 triangle shape sticks together.

*** now substitute ***
Rubber = steel matrix

Hard plastic cube = Iron carbide (cementite) or Chromium carbide.

Metal cube = Vanadium carbide

Knife = Chromium Oxide (Alumina in many waterstones, etc..)

Laser = Diamond/CBN

*** Conclusion ***
Major component of sharpening ease depends on carbide type&size + abrasive type/sharpness + sharpening. Most simples low-to-high carbon knives have smaller & softer carbide than stainless & high hard alloy knives. Some low alloy and or low rc and or lot of retained-austenite stainless steels can clog/glaze sharpening media, which lead to burnishing affect (instead of abrading), thus attributed to perception of harder to sharpen.