Ah, I see, I misunderstood. You would be surprised how often I'm bombarded with why ceramic can't cut vanadium carbide.
As for when is the exact amount that you absolutely, positively, always need diamond the most commonly held belief was if the steel has 4% wt Vanadium alloy in its chemistry then you need diamond.
(The amount of vanadium alloy % wt in the steel is not the same as volume of vanadium carbide in matrix)
However, it's not a "hard wall" where if you have 3.99% you're good to go and if you have 4% you are doomed to diamond.
It's more of a large fuzzy line near 4% wt V alloy in common knife steels where you'll notice the increasing vanadium carbide volume reduces the effectiveness of ceramic abrasive to shape the apex especially if the steel is at high hardness.
In my experience, I've had better results with diamond even going as low as on steels like Cru Forge V (cfv) which have significantly less than the 4% wt V rule.
So, if you are a discerning sharpener you may notice a crisper edge using diamond even on steels less than 4% wt V alloy like 3v, cruwear and cfv in my personal experience, for others it doesn't seem to be a big deal to just use ceramic on steels like these. ymmv but I don't think we're all getting them equally sharp, I think some people are just fine with the level of sharpness they are getting "as long as it cuts what I need it's good to go" to each their own, whatever works, unless you're trying to make comparisons about the steel sharpness capability of course.
I feel this can also be a bit of a loaded question because at the heart of the question it could be about trying your best to avoid diamond because of negative experiences with some Diamond Stones.
Unfortunately, people put all diamond stones in the same box; they are not all the same.
One of the many reasons why people don't like diamond stones is because of the deep scratches they leave.
Most people don't make the distinction between electroplated stones and bonded stones.
Bonded Stones use resin, vitrification or metallic powders to make a full thickness "stone" just like a waterstone. It's not just a coated layer like the electroplated stuff. The abrasive particles are not sticking up as far with bonded stones so they don't dig into the bevel as deep when you cut with them which also means the abrasive is less prone to tearing out and dulling. A bonded stone surface can also be refreshed to reveal new abrasive grains.
So, it's like an "everlasting gobstopper" so to speak in comparison to the coated electroplated stones.
What is the problem with deeper scratches from electroplated diamond?
As you may know, deeper scratches from the cheaper electroplated stones can mean bigger stress risers which can reduce edge stability and those scratches are more difficult to remove with higher grit.
The bonded diamond and cBN stones are nothing new, but it doesn't seem to be common knowledge yet for some that may be reading. Fortunately, the information seems to be slowly trickling out to people that bonded stones behave differently with less of the drawbacks of the electroplated stones except in cost of course.
I think folks should remember steels with excess carbide volume are not focused on the absence of sharpening.
It's about sharpening when you want to not because you have to. so it's worth also investing in good stones.
NCJohn62 wrote: ↑Sun Oct 09, 2022 2:02 pm
It is straightforward Shawn, I was actually asking about lesser carbide steels and not so much for my own knowledge but as a way to expand the conversation.
Deadboxhero wrote: ↑Sun Oct 09, 2022 11:33 am
I feel this is pretty straightforward.
Vanadium carbide 2800Hv (87 HRC)
Aluminum oxide (ceramic) 1800Hv (79 HRC)
Vanadium Carbide volume in CPM 15V is ~23%
Why are you going to use an abrasive that only sharpens 77% of the edge and then complain that it's too difficult to sharpen and not taking an edge?
NCJohn62 wrote: ↑Sun Oct 09, 2022 5:58 am
Shawn at what carbide volume do you feel that using ceramic stones becomes a exercise in futility?
Deadboxhero wrote: ↑Mon Oct 03, 2022 8:05 pm
Columbia Gorge Works
Naniwa
Nanohone
Practical Sharpening
Poltava
Venev
To name a few.
