Case CV/SS

[hughd]

It is my understanding that CV steel is harder than SS. Also, I am under the impression that CV is easier to sharpen. That seems counter intuitive to me. Please explain...

 

[black mamba]

The reason that CV steel is easier to sharpen than the Tru-Sharp stainless is partially due to the hardness. The chromium in the stainless steel, plus the lower hardness, makes it very likely to form a wire edge when sharpening. This wire edge is difficult to remove while keeping the sharpness you've already attained. So whether the wire edge remains (rounding the edge) or it's broken off unevenly (scattering the apex), you still end up with a less than sharp blade. I've found going to a more obtuse angle (20° instead of 15°) and putting very little pressure on the stones helps mitigate the wire edge forming.

 

[Old Hunter]

Stropping will also set the wire edge straight (until it gets rolled again). OH

 

[Obsessed with Edges]

It is my understanding that CV steel is harder than SS. Also, I am under the impression that CV is easier to sharpen. That seems counter intuitive to me. Please explain...

Neither is hard to sharpen, when you get right down to it. Hardness differences between them are insignificant as far as sharpening is concerned. A lot depends on if you're comfortable and adept and handling burrs that tend to form more often on low-alloy stainless. And a big part of that is in choosing abrasive types and methods that help to minimize burring in the first place.

I tend to not like using ceramics on the stainless for heavier work, as they're more prone to inducing burring on such stainless, especially if pressure used is a little bit heavy. Aside from that, any stone or hone that cuts the steel cleanly at light pressure is a good choice for this stainless. Aluminum oxide stones (oilstones, waterstones) at relatively coarse/medium grit (220 - 400) work well for heavier work. And for finishing, Arkansas stones or finer-grit aluminum oxide or silicon carbide (SiC), or even diamond at Fine/EF grit, all work well. And if your light touch is well-tuned and featherlight, then the ceramics can also work very well at the finishing & touch-up end.

The CV is generally 'easier' to sharpen because it contains virtually no hard carbides at all (chromium carbides, vanadium carbides, etc). It's therefore faster to grind on the simplest of stones. And it's less prone to burring than the stainless, which means it needs less cleaning up after the stone work (CV being slightly harder CAN make some difference here, in a good way). I think it responds the best to either Arkansas stones or medium/fine-grit aluminum oxide stones. But something like a 320-400 grit SiC stone can also leave a nice finish on a CV blade's edge.

After getting comfortable sharpening both, I tend to treat them virtually identically in terms of which stones I use and the finish I choose for their edges. Around ~ 320 or so is a really nice match for them, using either fine-grit AlOx oilstones ('India' stones, etc) or a medium/soft Arkansas. The only difference is, a little more attention is needed for minimizing and cleaning up the burrs on the stainless. If you're accustomed to handling that, they sharpen up in virtually indistinguishable comparison and they're very, very easy to live with.

 

[Dangerously]

I’m glad to read the sharpening tips on the stainless here. I have a couple of case stainless knives, and hate sharpening them. It feels like making tin foil, with how large the burrs get. I don’t have this problem with any modern high alloy stainless steels. Makes me understand how people years ago complained that stainless steel was terrible.

I used to refine and finish on Spyderco ceramics, but I’ll take the advice and go back to finishing with a DMT EF and see if that helps. Maybe it’s better with the waterstones, too.

 

[Hickory n steel]

I've never had to fully sharpen either of my tru-sharp knives, I just keep the edge touched up on the bottom of a coffee mug.
I do this with all my knives and rarely go to a stone.

 

[Modoc ED]

I mostly use either a Norton Crystolon Stone or a Lansky 4-rod Turn Box Crock Stick Sharpener for both CV and Tru-Sharp sharpening. Either one puts a very good edge on those steels as well as most other steels. Sometimes, I use a Spyderco Sharpmaker as well.

 

[Dangerously]

I've never had to fully sharpen either of my tru-sharp knives, I just keep the edge touched up on the bottom of a coffee mug.
I do this with all my knives and rarely go to a stone.

That’s a great idea when the blades don’t come the factory ground into a wavy mess.

 

[Hickory n steel]

That’s a great idea when the blades don’t come the factory ground into a wavy mess.

Mine didn't, but even when I do get a knife without a perfect edge grind I don't care as long as the knife still cuts.

 

[hughd]

The reason that CV steel is easier to sharpen than the Tru-Sharp stainless is partially due to the hardness. The chromium in the stainless steel, plus the lower hardness, makes it very likely to form a wire edge when sharpening. This wire edge is difficult to remove while keeping the sharpness you've already attained. So whether the wire edge remains (rounding the edge) or it's broken off unevenly (scattering the apex), you still end up with a less than sharp blade. I've found going to a more obtuse angle (20° instead of 15°) and putting very little pressure on the stones helps mitigate the wire edge forming.

Neither is hard to sharpen, when you get right down to it. Hardness differences between them are insignificant as far as sharpening is concerned. A lot depends on if you're comfortable and adept and handling burrs that tend to form more often on low-alloy stainless. And a big part of that is in choosing abrasive types and methods that help to minimize burring in the first place.

I tend to not like using ceramics on the stainless for heavier work, as they're more prone to inducing burring on such stainless, especially if pressure used is a little bit heavy. Aside from that, any stone or hone that cuts the steel cleanly at light pressure is a good choice for this stainless. Aluminum oxide stones (oilstones, waterstones) at relatively coarse/medium grit (220 - 400) work well for heavier work. And for finishing, Arkansas stones or finer-grit aluminum oxide or silicon carbide (SiC), or even diamond at Fine/EF grit, all work well. And if your light touch is well-tuned and featherlight, then the ceramics can also work very well at the finishing & touch-up end.

The CV is generally 'easier' to sharpen because it contains virtually no hard carbides at all (chromium carbides, vanadium carbides, etc). It's therefore faster to grind on the simplest of stones. And it's less prone to burring than the stainless, which means it needs less cleaning up after the stone work (CV being slightly harder CAN make some difference here, in a good way). I think it responds the best to either Arkansas stones or medium/fine-grit aluminum oxide stones. But something like a 320-400 grit SiC stone can also leave a nice finish on a CV blade's edge.

After getting comfortable sharpening both, I tend to treat them virtually identically in terms of which stones I use and the finish I choose for their edges. Around ~ 320 or so is a really nice match for them, using either fine-grit AlOx oilstones ('India' stones, etc) or a medium/soft Arkansas. The only difference is, a little more attention is needed for minimizing and cleaning up the burrs on the stainless. If you're accustomed to handling that, they sharpen up in virtually indistinguishable comparison and they're very, very easy to live with.

GRATE information! Thank you both for taking the time to clear this up for me and others.