Finishing grit for skinning knives?

Eli Chaps said:
So I think, regardless of stone type, one pretty common theme in the recommendations has been that for what you want, lower grits are preferred. You seem committed to higher polish.
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Oh, sorry I wasn't clear. I originally asked about skinning knives, which from my understanding now in that case I should stop after my 320 grit stone, and strop a bit. The conversation turned into a discussion of getting good performance out of a high polish, which I prefer for my edc. I think I'll try a low grit finish next time I need to skin but I am trying to go for the best polished edge possible for my edc folders, which are an s30v benchmade and m390 We Practic.
 
The edge prep is only as good as the steel you put it on.

Lots of factors like Actual steel hardness, alloy content and blade geometry will all come into play when selecting edge angle and edge prep for a given task.

Example 1: Many years ago I was hunting with my uncle (The guy who also taught me how to sharpen), he shot a buck and it was not long before he was calling me over because his trusty Case sodbuster was too dull to start the field dressing process. I handed him an old Cold Steel knife in Aus8 freshly sharpened on a Medium Arkansas stone (my first stone). The sharp edge easily slid through the hide and made short work of field dressing. The edge needed a little work after the field dressing and while skinning and butchering it also needed a few trips to the stone, probably 4-5 times total. This is an example of a knife that could have used a coarser edge for the task... and a steel thats not up to the task.

Example 2: A handful of years ago I let a friend borrow my Spyderco Mule Team in 52100 @HRC62 IIRC. This is a thin flat ground blade of hard ball bearing steel, the edge was ground to about 30 degrees inclusive and polished to 10,000 grit on Japanese waterstones. On his trip he filled two tags and field dressed two Bucks. Though not a lot of work like example one its still the toughest part of the job and when the knife returned to me there was hardly any wear, the knife would still pop hairs and at worst had one small deformation from bone contact. This is an example of a good steel with a carefully selected edge to yield the maximum performance... and a steel that can handle it.

High alloy steels change things up, steels with 4% or greater Vanadium content rely on the carbides in the steel for edge retention. If you polish these edges then you "lock in" the carbides in the fine polished surface not allowing them to be exposed and work as intended. The coarser edge leaves the steel surface "Open" exposing the carbides and allowing them to contribute to edge retention. So on your S30V and M390 it would do you a disservice to polish the edges. I would recommend a DMT Coarse and strop coated in 1 micron diamond, ask around, its popular.

Lastly, in general a coarser edge is the longer lasting option when speaking purely of edge retention, Its even proven in CATRA testing, but if pure edge retention was our only concern knife makers would only make serrated knives.
 
Jason B. said:
The edge prep is only as good as the steel you put it on.

Lots of factors like Actual steel hardness, alloy content and blade geometry will all come into play when selecting edge angle and edge prep for a given task.

Example 1: Many years ago I was hunting with my uncle (The guy who also taught me how to sharpen), he shot a buck and it was not long before he was calling me over because his trusty Case sodbuster was too dull to start the field dressing process. I handed him an old Cold Steel knife in Aus8 freshly sharpened on a Medium Arkansas stone (my first stone). The sharp edge easily slid through the hide and made short work of field dressing. The edge needed a little work after the field dressing and while skinning and butchering it also needed a few trips to the stone, probably 4-5 times total. This is an example of a knife that could have used a coarser edge for the task... and a steel thats not up to the task.

Example 2: A handful of years ago I let a friend borrow my Spyderco Mule Team in 52100 @HRC62 IIRC. This is a thin flat ground blade of hard ball bearing steel, the edge was ground to about 30 degrees inclusive and polished to 10,000 grit on Japanese waterstones. On his trip he filled two tags and field dressed two Bucks. Though not a lot of work like example one its still the toughest part of the job and when the knife returned to me there was hardly any wear, the knife would still pop hairs and at worst had one small deformation from bone contact. This is an example of a good steel with a carefully selected edge to yield the maximum performance... and a steel that can handle it.

High alloy steels change things up, steels with 4% or greater Vanadium content rely on the carbides in the steel for edge retention. If you polish these edges then you "lock in" the carbides in the fine polished surface not allowing them to be exposed and work as intended. The coarser edge leaves the steel surface "Open" exposing the carbides and allowing them to contribute to edge retention. So on your S30V and M390 it would do you a disservice to polish the edges. I would recommend a DMT Coarse and strop coated in 1 micron diamond, ask around, its popular.

Lastly, in general a coarser edge is the longer lasting option when speaking purely of edge retention, Its even proven in CATRA testing, but if pure edge retention was our only concern knife makers would only make serrated knives.
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Really good post Jason. Thank you.
 
Jason B. said:
The edge prep is only as good as the steel you put it on.

Lots of factors like Actual steel hardness, alloy content and blade geometry will all come into play when selecting edge angle and edge prep for a given task.

Example 1: Many years ago I was hunting with my uncle (The guy who also taught me how to sharpen), he shot a buck and it was not long before he was calling me over because his trusty Case sodbuster was too dull to start the field dressing process. I handed him an old Cold Steel knife in Aus8 freshly sharpened on a Medium Arkansas stone (my first stone). The sharp edge easily slid through the hide and made short work of field dressing. The edge needed a little work after the field dressing and while skinning and butchering it also needed a few trips to the stone, probably 4-5 times total. This is an example of a knife that could have used a coarser edge for the task... and a steel thats not up to the task.

Example 2: A handful of years ago I let a friend borrow my Spyderco Mule Team in 52100 @HRC62 IIRC. This is a thin flat ground blade of hard ball bearing steel, the edge was ground to about 30 degrees inclusive and polished to 10,000 grit on Japanese waterstones. On his trip he filled two tags and field dressed two Bucks. Though not a lot of work like example one its still the toughest part of the job and when the knife returned to me there was hardly any wear, the knife would still pop hairs and at worst had one small deformation from bone contact. This is an example of a good steel with a carefully selected edge to yield the maximum performance... and a steel that can handle it.

High alloy steels change things up, steels with 4% or greater Vanadium content rely on the carbides in the steel for edge retention. If you polish these edges then you "lock in" the carbides in the fine polished surface not allowing them to be exposed and work as intended. The coarser edge leaves the steel surface "Open" exposing the carbides and allowing them to contribute to edge retention. So on your S30V and M390 it would do you a disservice to polish the edges. I would recommend a DMT Coarse and strop coated in 1 micron diamond, ask around, its popular.

Lastly, in general a coarser edge is the longer lasting option when speaking purely of edge retention, Its even proven in CATRA testing, but if pure edge retention was our only concern knife makers would only make serrated knives.
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Wow, that gives me a little more respect for Spyderco's 52100 heat treat. I think I am going to use my 320 grit shapton glass stone to put a skinning edge on knives in the future, and see how that works for me. IMO polished edges are more for EDC and some kitchen knives.
 
Use the SG500, much better edge.

FYI, Spyderco gets the HT right, not just on 52100 (folders are not the same hardness fyi) but on all the steels they put out.
 
The 500 will provide a much cleaner edge with less fuss getting there. It is more of a sharpening stone than a grinding stone where the 320 is still for grinding and shaping. The SG320 is not what I would consider good at making edges either, again, the cleanliness of the apex is difficult to achieve with the 320.

And while I'm completely aware that Shapton Glass stone will do pretty well on the High Alloy steels mentioned (at least to 1k) they will still not do as good as diamonds. There will be a lot of edge keenness/sharpness missing comparatively and will likely result in poor edge performance.

Some random thoughts,
Buy a DMT Coarse/Fine Diafold and carry it with you hunting. Cut down a paint stick, coat it in diamond spray and rubber band it to the diafold... BAM! field honing kit perfect for the steels you need to sharpen.
 
I remember in my younger years skinning beaver and how tough that was on a knife edge. Is anyone using these high vanadium steels in this type of application and if so how do you sharpen it and how often? I just can't see having a knife in the skinning shed that I had to sharpen on machines or to a feather razor like polish.
 
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
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I bought a Venev 800/1200 plate which is supposedly 6 micron and 2.5 micron resin bonded diamond. I went from my Suehiro Cerax 1000 AlO stone (not ideal) to the 6 micron side of the venev, and made sure to spend extra time to remove all of the 1000 grit scratches before polishing on 2.5 micron venev and 1um, 0.5um diamond loaded strops. You are correct, absolutely I can see that diamonds do something for high vanadium steels that you just cant get from anything else besides CBN, which I haven't yet tried. I feel like this thread has come full circle, and I now fully agree with your assertion. I will be getting a coarser grit venev as well so I can get the maximum benefit. I am having a bit of a problem though with stray scratches that are bigger than the finish level of the stone, I think something to do with the diamonds clumping. These are the OCB versions. Maybe I am using too much pressure, or gouging the stone a bit without realizing it. They do give feedback, but not as much and a bit different from japanese style stones. The edge I got though was clearly better. I am looking forward to finding out how much better my Spyderco Sage 1 holds its edge.
 
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