Finishing grit for skinning knives?

ToddS said:
proper is a bit subjective, but I would point out that the factory edge on my Spyderco Maxamet Native and S110V Para 2 were carbides exposed by buffing.
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Hmm, so that sounds like something I could approximate on a strop with diamond paste.
 
Any pictures out there on what these high vanadium carbide steels look like under magnification coming off of naturals, JNATS, Arks ect?
 
The shapton will burnish the M4 too much in my experience.

I recommend a 400grit metallic bonded CBN/Diamond stone and a 1um diamond spray strop.

Should give the perfect blend of sharpness and aggressive bite for hide, silver skin, etc for that task.



nutsforknives said:
Does anyone have experience specifically with skinning? I tried to skin a hog with my spyderco sage because it was in my pocket at the time, but it had a fairly polished edge (6k, stropped with flitz polish) and didn't work as well as the cheap butcher knives lying around the skinning rack.They seemed to have coarse edges and the guy I was skinning with used a steel to bring the edge back a couple times (hog skin is quite tough).

I have a Spyderco Gayle Bradley that I want to set up for skinning. I'm thinking about putting either a 320 or 1000 grit edge on it with my shapton glass/suehiro waterstones. Does that sound right for a skinning knife? What do you guys do?
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nutsforknives said:
Do you think stropping with diamond paste after using japanese whetstones would do the trick, or would I need to use diamonds all the way through? I already have a 140 grit diamond plate, but my 320,1k,5k and 8k are all Japanese stones. I do have a couple leather strops loaded with 1 micron and 0.5 micron diamond paste. What equipment/procedure would you suggest for putting a proper edge on high vanadium knives? I would consider buying a high grit diamond plate for finishing the edge. Would a DMT Dia-sharp EF or EEF do it?
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If you don’t have coarse diamond or CBN, it is OK to grind bevels of your wear-resistant blade with a coarse silicon carbide abrasive; however, setting the edge apex and honing must be done with diamonds/CBN for the lasting sharp edge. Honing the wear-resistant edge with conventional compounds, including fine ceramic hones, is the main cause of them dulling early – if you use them on your high-end knife, it may perform even worse than a mainstream knife.

We've sharpened premium knife steels both ways, testing the sharpness and edge stability to rolling - and the conclusion is that for the best results, from the #1000 and finer must be diamonds or CBN.

Sorry to say that, but by my experience, what you have is not adequate for sharpening wear-resistant blades.
Moreover, for the best outcome one needs some angle-controlled sharpening method, rather than sharpening freehand on diamond plates.

Todd is the most comprehensive source of SEM images, available on his website http://scienceofsharp.com. I think Todd knows more than anyone about knife and razor sharpening, and I've learned a lot by reading his comments.

If you re-read Todd's description to the MAXAMET SEM images, he set the edge apex on #1200 diamonds, and honed with 1-micron diamonds.
We do it similarly, but somewhat differently in that, having set the apex on #1000 CBN, we then hone wear-resistant knives with a progression of diamonds from 10-microns to 0.25 microns. E.g. see our detailed protocol in the video
 
I should point out that I increase the angle by 1/2 a degree between the 1200 grit and the 1 micron diamond film, so it's an easy "jump" in grit.
 
wootzblade said:
If you don’t have coarse diamond or CBN, it is OK to grind bevels of your wear-resistant blade with a coarse silicon carbide abrasive; however, setting the edge apex and honing must be done with diamonds/CBN for the lasting sharp edge. Honing the wear-resistant edge with conventional compounds, including fine ceramic hones, is the main cause of them dulling early – if you use them on your high-end knife, it may perform even worse than a mainstream knife.

We've sharpened premium knife steels both ways, testing the sharpness and edge stability to rolling - and the conclusion is that for the best results, from the #1000 and finer must be diamonds or CBN.

Sorry to say that, but by my experience, what you have is not adequate for sharpening wear-resistant blades.
Moreover, for the best outcome one needs some angle-controlled sharpening method, rather than sharpening freehand on diamond plates.

Todd is the most comprehensive source of SEM images, available on his website http://scienceofsharp.com. I think Todd knows more than anyone about knife and razor sharpening, and I've learned a lot by reading his comments.

If you re-read Todd's description to the MAXAMET SEM images, he set the edge apex on #1200 diamonds, and honed with 1-micron diamonds.
We do it similarly, but somewhat differently in that, having set the apex on #1000 CBN, we then hone wear-resistant knives with a progression of diamonds from 10-microns to 0.25 microns. E.g. see our detailed protocol in the video
Click to expand...

Thanks, that is useful. I really enjoy sharpening freehand and forming a smoothly radiused convex edge, so I probably won't buy an angle guide system but I may pick up an EF and an EEF DMT dia-sharp plate at some point. That would get me #1200/9 micron and #8000/3 micron diamond abrasives. After that I have the 1 and 0.5 micron diamond paste. Do you think that would have the desired effect?
Separate question, I am still confused by the maxamet article. Why does he claim that finishing on a #8000 Shapton glass (resin bound ceramic, I am pretty sure), increases edge aggression and retention?
 
nutsforknives said:
...Separate question, I am still confused by the maxamet article. Why does he claim that finishing on a #8000 Shapton glass (resin bound ceramic, I am pretty sure), increases edge aggression and retention?
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The 8k Shapton glass (with a bit of slurry) does not cut the carbides, only the matrix around them, duplicating the factory edge, which has excellent slicing aggression.
 
ToddS said:
The 8k Shapton glass (with a bit of slurry) does not cut the carbides, only the matrix around them, duplicating the factory edge, which has excellent slicing aggression.
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nutsforknives said:
Thanks, that is useful. I really enjoy sharpening freehand and forming a smoothly radiused convex edge, so I probably won't buy an angle guide system but I may pick up an EF and an EEF DMT dia-sharp plate at some point. That would get me #1200/9 micron and #8000/3 micron diamond abrasives. After that I have the 1 and 0.5 micron diamond paste. Do you think that would have the desired effect?
Separate question, I am still confused by the maxamet article. Why does he claim that finishing on a #8000 Shapton glass (resin bound ceramic, I am pretty sure), increases edge aggression and retention?
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Edge aggression and retention is reduced with a 8k shapton for skinning, especially with a high vanadium super steel at high hardness.
 
To a lower grit CBN/Diamond in the 400-1000grit range.

Also there are more stones available in diamond/cbn than just "plates" that offer more features to finish and cutting speed.

Metallic, resin, and vitrified bonded diamond/CBN.
nutsforknives said:
Reduced relative to what? an 8k diamond plate?
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nutsforknives said:
Thanks, that is useful. I really enjoy sharpening freehand and forming a smoothly radiused convex edge, so I probably won't buy an angle guide system but I may pick up an EF and an EEF DMT dia-sharp plate at some point. That would get me #1200/9 micron and #8000/3 micron diamond abrasives. After that I have the 1 and 0.5 micron diamond paste. Do you think that would have the desired effect?
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That's the way to go - you will see a drastic performance improvement in your premium knives. I'd only be cautious about the Extra-Extra Fine diamond plate, because of its relatively short lifespan. I'd set the edge apex on the EF, and continue on diamond strops.

On diamonds (or CBN) we can sharpen wear-resistant steels with little pressure, as compared to stones, minimizing that "tired edge" with poor retention that we get off the stones.
The steel matrix around the vanadium carbides does not get eroded, and the carbides themselves are shaped sharp towards the edge.

Without diamonds we get on premium knives just a "working edge", while with diamonds we put on them a lasting shaving edge.
 
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DeadboxHero said:
To a lower grit CBN/Diamond in the 400-1000grit range.

Also there are more stones available in diamond/cbn than just "plates" that offer more features to finish and cutting speed.

Metallic, resin, and vitrified bonded diamond/CBN.
Click to expand...

Ahh that makes sense. Do you have any recommendations for sharpening products to check out? I am trying to get really good at freehand sharpening so I've been looking at the DMT dia-sharp continuous diamond plates. Are there alternatives that you think I should look at? Keep in mind I do not have any guided system or motorized grinding hardware.
 
wootzblade said:
That's the way to go - you will see a drastic performance improvement in your premium knives.
On diamonds (or CBN) we can sharpen wear-resistant steels with little pressure, as compared to stones, minimizing that "tired edge" with poor retention that we get off the stones.
The steel matrix around the vanadium carbides does not get eroded, and the carbides themselves are shaped sharp towards the edge.

Without diamonds we get on premium knives just a "working edge", while with diamonds we put on them a lasting shaving edge.
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Ok, you have convinced me to give it a shot. Some time soon I'll get some diamond plates. Do you think I should go with DMT or are there other brands/products I should check out? Keep in mind I am sticking with sharpening freehand on bench stones.
 
I also freehand.

I recommend the venev diamond resin stones to start with. They are better than the DMT plates in finishing and longevity.

I'm more partial to other stones but the venevs are more affordable.

nutsforknives said:
Ahh that makes sense. Do you have any recommendations for sharpening products to check out? I am trying to get really good at freehand sharpening so I've been looking at the DMT dia-sharp continuous diamond plates. Are there alternatives that you think I should look at? Keep in mind I do not have any guided system or motorized grinding hardware.
Click to expand...
 
DeadboxHero said:
I also freehand.

I recommend the venev diamond resin stones to start with. They are better than the DMT plates in finishing and longevity.

I'm more partial to other stones but the venevs are more affordable.
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Thanks, I now have a new grail stone! Well, one or two... Considering the price for two sided plates I am seeing on Amazon, its also slightly more affordable than buying multiple DMT plates. This is exactly the type of esoteric knowledge I am seeking. Just to go a bit deeper down the rabbit hole though, what are your absolute favorite stones?
 
wootzblade said:
If you don’t have coarse diamond or CBN, it is OK to grind bevels of your wear-resistant blade with a coarse silicon carbide abrasive; however, setting the edge apex and honing must be done with diamonds/CBN for the lasting sharp edge. Honing the wear-resistant edge with conventional compounds, including fine ceramic hones, is the main cause of them dulling early – if you use them on your high-end knife, it may perform even worse than a mainstream knife.

We've sharpened premium knife steels both ways, testing the sharpness and edge stability to rolling - and the conclusion is that for the best results, from the #1000 and finer must be diamonds or CBN.
Click to expand...

Could you define "setting the edge apex" in this context, and is this a change in recommendation since the exchange below where you wrote that an edge apexed with conventional abrasives and honed with diamonds will have properties of [an] all-diamond sharpened edge?

Mr.Wizard said:
I just read the report Edge Rolling in High Vanadium Knives Sharpened with Aluminium Oxide versus CBN/Diamond and I have a question. Did you do any testing of mixing abrasives types, i.e. shaping on aluminum oxide and finishing on 3 micron diamond, or shaping on cBN and finishing with the Tormek compound? If not would you consider doing this for Elmax where the effect was most dramatic?
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wootzblade said:
We can tell without exhaustive testing that an edge apexed with conventional abrasives and honed with diamonds will have properties of all-diamond sharpened edge, while the edge apexed with diamonds/CBN but honed with conventional compounds like Totmek honing paste will have properties of all-Al2O3 sharpened.
This is because weakening of the steel matrix happens during fine honing, not bevelling.
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I was wrong saying that the apex can be set on either. My excuse is that back then I was moving from stones to CBN and diamonds and was still exploring the subject.

Well-known three steps in sharpening a knife are:
1) grinding the bevels on grits from coarse to fine,
2) setting the edge on a fine grit, also called “apexing”, and
3) deburring

So, "setting the edge apex" is the finest grinding # we raise the burr on, after which we proceed to deburring.

I know more now, than I knew in the year of that post you quote. Today I know that setting the edge apex with superabrasives will always win over the stones, natural or artificial, for any knife steel, mainstream or premium.

I don't really want to open a can of worms here in this thread, but now that I've said that, I simply have to give some reasoning.

Comparison between conventional abrasives (aluminium oxide or silicon carbide) and “superabrasives” (CBN cubic boron nitride or diamond) tells us that:
For conventional abrasives burrs tend to be long, whereas for superabrasives the burrs tend to be relatively small and easier to deburr.
CBN and diamond abrasives remove material in a unique way: due to their super hardness the whole process is quite similar to the milling operation, while conventional abrasives are more akin to sanding - as a result, the edge we get on superabrasives has less variation in the apex width.
Blades are sharpened on CBN and diamonds with light pressure and stress the edge less.
All these moments give the edge ground with CBN and diamonds a stronger apex and eventually better lasting sharpness.

It is good that Todd looked into this thread, as he may correct me if I am wrong saying that setting the edge on an abrasive near the #1000 (#800 - #1200), the edge apex we get on a stone will never be as sharp as on the CBN/diamond. Explained on our website here: http://knifegrinders.com.au/Manuals/SEM.pdf

I probably should stop here and apologize for derailing this thread into the debate of stones vs diamonds.
 
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