So maybe a stupid question… but what is a full convex edge vs…. What other kind of convex edge?? I understand what convexity is but can someone define the various terms we use to describe what is “convex”.
Stupid question? Defining full convex
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A full convex is like a zero grind but with curves. There is no edge bevel. Full convex rounds from the blade grind into the cutting apex.
Bark River Knives of EDC popularity is an example that gets a lot of discussion.
I don't like it.
Bark River Knives of EDC popularity is an example that gets a lot of discussion.
I don't like it.
Well, I should be more specific. I specifically don't like a full convexed edge on EDC/outdoor/hunting knives. Too difficult to maintain properly. People recommend using mouse pads with sandpaper so the substrate has give to conform to the edge. Bah. Their trumpeted as being a more robust edge but I've never been convinced and even if there is some tiny benefit, I think it's wiped out by being thicker and more difficult to sharpen.
Now, on thinner kitchen knives I reckon it's a bit different as the downsides are less pronounced.
I absolutely do believe in convexing, even down the edge but I like a distinct edge bevel if for no other reason than ease of routine maintenance.
tostadas
Hobbyist / Craftsman
To me, full convex means no low spots.
Theorically yes!
I am going to jump in with an opinion. If the knife has from the maker 'full convex edge' and then user just puts a little microbevel on it during sharpening, but once the edge needs thinning it gets back its 'full convex', I would still consider it 'full convex'. I don't think that a microbevel will in any meaningful way change the way a full convex knife cuts.
tostadas
Hobbyist / Craftsman
Agree with that . I don't think anyone calls something with flat to shinogi a convex grind though.
When I see the term “full convex” I assume there are no low spots and there is no shinogi line. The convexity doesn’t have to extend all the way to the spine (i meant this as a walkschliff/clam shell grind) but I guess it could.
A belt finished convex grind with no shinogi line is just a convex grind in my mind.
A belt finished convex grind with no shinogi line is just a convex grind in my mind.
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Why is no low spots important here in the convex?
My understanding of low spots is that along the face of the blade it is all the same level in the same horizontal plane? Unless I am not defining it correctly.
@Bico Doce why a belt finish without a shinogi? I assume it’s because shinogi makes it a wide bevel and therefore it cannot be a convex?
My understanding of low spots is that along the face of the blade it is all the same level in the same horizontal plane? Unless I am not defining it correctly.
@Bico Doce why a belt finish without a shinogi? I assume it’s because shinogi makes it a wide bevel and therefore it cannot be a convex?
tostadas
Hobbyist / Craftsman
Some blades are mainly convex with some concavity. For example a myojin grind tends to have some concave near the edge. I wouldn't consider that to be "full convex".
Maybe getting too nuanced comparing vertical to longitudinal low spots. How bout this, if you lay the blade on its side and run a straight edge along it, perpendicular to the spine, you should be able to rock it at any given point and see no "holes" when doing so.
Gotcha. I’m following thanks mate 
Is the famous "Walkschliff" that is known for example from Isasmedian knives also a fully convex design?
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Thank you, @Nemo
For convex face and edge, think the way Opinel are ground. Or the right face on a hankotsu or honesuki. The very edge is less than a line. The idea is to have at least on the dominant side of a yo-gyuto, a continuous arc formed by both face and bevel. By the way, @miggus 's Walkschliff supposes the blade is thinned as well near the spine.
To remove all facetting after realising a convex edge I use a medium fine stone — a NP Chosera 2k — looking for points where the bevel offers any resistance. Flat one the stone, gently moving edge leading. Give it ONE light stroke at that angle, and go back to the initial position, flat on the stone. With carbons, expext some four strokes to be needed. A bit more of them with more abrasive resistant stainless.
If thinned enough BTE a convex bevel shouldn't impair performance, but highly improve edge retention.
With highly charged stainless I've seen that an unstable edge can be highly improved with some extra convexing close to the very edge. Some rounding is in this case beneficial.
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Corradobrit1
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Isn't Kato doing full convex on his Migaki blades? At least thats my impression.
I use the term to describe geometries in which the entirety of the blade is convex from spine to edge. Unless stated otherwise, I don't assume it will be free of all low spots. However, I will assume a lack of any intentionally flat or hollow areas.
I've always taken it to mean continuous convexity across the blade face excluding the secondary bevel if any.
I always thought a convex edge is different than a full convex grind. Hmmm
Fair enough, but I've never seen anyone here describe an apex as "full convex" and only seen that term used when describing grinds. Don't see much talk of convex edge-sharpening here, probably because the behind the edge geometry of a good kitchen knife is so thin as to make it less relevant than with something like a folder or outdoor knife.
TheDza
Senior Member
anyone have any handy diagrams to help out with visualization?
Everyone is giving good info so ill add another tidbit.
Joe from HF uses “full” convex grind term on his honyakis and some monos but when its just a stainless clad, dammy (sometimes), or mono (but cheaper finish) its just a convex grind.
Looks like when he uses “full” it encapsulates the geometry at a whole, not just the lower 1/4 if the blade near the edge. I’ve had a few of his full convex knives, they are nice. Sometimes wedge too much when paired with WH build. But when its a middleweight, perfect.
Full convex for me is more sculpted full blade geometry. Just convex is convexity at some point along the blade road, usually closer to the edge. I see him just say convex when the blades are less finished and usually thinner overall.
Forge the blade, thin the lower bevel, then convex it on the rotary.
Vs forge the blade then start the convexity higher up and gradually lower it until you meet the edge. Also probably at measurement he is trying to meet at every point of the blade. Usually comes with a full polish.
Joe from HF uses “full” convex grind term on his honyakis and some monos but when its just a stainless clad, dammy (sometimes), or mono (but cheaper finish) its just a convex grind.
Looks like when he uses “full” it encapsulates the geometry at a whole, not just the lower 1/4 if the blade near the edge. I’ve had a few of his full convex knives, they are nice. Sometimes wedge too much when paired with WH build. But when its a middleweight, perfect.
Full convex for me is more sculpted full blade geometry. Just convex is convexity at some point along the blade road, usually closer to the edge. I see him just say convex when the blades are less finished and usually thinner overall.
Forge the blade, thin the lower bevel, then convex it on the rotary.
Vs forge the blade then start the convexity higher up and gradually lower it until you meet the edge. Also probably at measurement he is trying to meet at every point of the blade. Usually comes with a full polish.
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Man. All of this is gold. Thanks guys
