Thread: shap16k+Cro = ch12k+Cro

ooh.... a shiny new forum....

So here it is: If I properly use a ch12k followed by CrO, I feel like it's just as good as a shap 16k with CrO. I'm even considering selling the 16k.

Whatcha think?

anything+CrO = CrO.

Verhoeven looks at this under an electron microscope in his paper "Experiments in Knife Sharpening".

The hones you use before the final polish don't matter to the final edge, since work they've done is abraded away during the final polish. He tried moving up the progressions slowly then finishing with CrO, vs jumping straight from I think 2k to CrO, and the end results were the same at 10,000x magnification. So use whatever you prefer - whatever gives you the best or most familiar feedback, or is the fastest, or is the cheapest, or the prettiest stone. The only part that's important is that if you want a CrO type edge, then finish on CrO (or if you want a 30k shapton finish then do whatever and just finish on that shapton, etc).

Originally Posted by mparker762

The only part that's important is that if you want a CrO type edge, then finish on CrO (or if you want a 30k shapton finish then do whatever and just finish on that shapton, etc).

I am not disagreeing with the above but this from the Shapton USA "How to use Shapton stones" should be remembered along with it;

"The most important concept when using the Shapton system is achieving consistancy at a given grit level before moving up to the next finer stone. At the 2000 grit level, your tool should be perfectly shaped.

It is ineffective to attempt to reshape your tool at any finer grit level. If you have built a good foundation at the coarse grit level, very little work will be required at the finer grit levels."

I do like how that Consistency word keeps popping up.....

I have heard that somewhere, sometime................

Lynn

Originally Posted by JimmyHAD

I am not disagreeing with the above but this from the Shapton USA "How to use Shapton stones" should be remembered along with it;

"The most important concept when using the Shapton system is achieving consistancy at a given grit level before moving up to the next finer stone. At the 2000 grit level, your tool should be perfectly shaped.

It is ineffective to attempt to reshape your tool at any finer grit level. If you have built a good foundation at the coarse grit level, very little work will be required at the finer grit levels."

That is true, but it is true for any progression and isn't specific to Shapton, so this point, while correct, is nonetheless orthogonal to the OP's question. Whether the bevel is set correctly before moving to the next stone or not, all traces of the previous stone's work will be obliterated by the next step in the progression if all goes well, so it doesn't matter which stone the bevel was set with (or not set with, as the case may be). The only hone that leaves any impact on the character of the edge will be the last one. I guess you could go from the 2k hone straight to chrome oxide for 1 lap or something, but that's kind of an odd thing to do.

Originally Posted by mparker762

That is true, but it is true for any progression and isn't specific to Shapton,

Absolutely and I thought about interjecting "or any other hone" into the quote from the Shapton website but it seemed obvious that it applies to any series of abrasives.

The example they give of a 2k is also applicable up the grit progression IMO. IOW, if you go from a 2 to a 4 to a 30 you won't get as satisfactory as result as you would have gotten going 2, 4, 8, 16 and 30. At least that is my assumption. I've not tried to shortcut the grit progression myself.

Ive done that progression on kitchen knives at a gathering, testing stone progerssion. Going from 2-4-8-16 results in a finer polish, by jumping these stone ranges to much you end up with haze, an unfinished polish. No mater how much work is done at the end. By using just enough strokes at closer stone grits you fully remove the last stones groove pattern. Thus at the last polishing stone you get the fully polished edge.

Some may not be excited to have that purfect polish, but there is a hair width level of performance there. I'm not hugh into purfect polishes and never really worried about the progerssion issue till I talked to a few others about it. What I learned was that the time and wear factors on each stone where greatly shortened by having a closer grit ladder. Less wear means longer life and less $$ lost

Originally Posted by JimmyHAD

The example they give of a 2k is also applicable up the grit progression IMO. IOW, if you go from a 2 to a 4 to a 30 you won't get as satisfactory as result as you would have gotten going 2, 4, 8, 16 and 30. At least that is my assumption. I've not tried to shortcut the grit progression myself.

Actually Verhoeven looked at this in his paper. He found that even if you short-circuited the progression the higher grits would eventually produce the exact same edge they would had you gone up normally. It took more than 1 or 2 laps to do it, for obvious reasons, but once the two edges were equivalently sharp there was no way to tell which one had been taken up the progression and which one had gone straight from 2000 to CrOx.

Originally Posted by mparker762

Actually Verhoeven looked at this in his paper. He found that even if you short-circuited the progression the higher grits would eventually produce the exact same edge they would had you gone up normally. It took more than 1 or 2 laps to do it, for obvious reasons, but once the two edges were equivalently sharp there was no way to tell which one had been taken up the progression and which one had gone straight from 2000 to CrOx.

I wonder if there was a time comparison taken into consideration between using a standard grit progression as opposed to going from 2k to chrom ox ? I would think the latter would require much more time and effort ?

Of course there is a time issue if you jump to the higher grits too soon. I don't remember how many Verhoeven had to do on the chrome oxide, but IIRC it was several times as many as he did when he was coming off the intermediate waterstone. For the intermediate hones it's really a matter of preference - honing feel, honing speed, or aesthetic value if you like pretty hones. For the final polish that's where you're worrying about the sort of edge you like, where you really sweat the light pressure and even strokes. If you like the feel of chrome oxide but worry that too much of it ovals the bevel then maybe you want to use something that only needs a few laps on CrOx to get that characteristic edge, like a Shapton 30k or Nakayama or get really good with the coticule or escher. Or just put your CrOx on hardwood so it won't oval the bevel no matter how many laps you do...