Do You Micro-Convex?

[redsquid2]

There is this guy on youtube who has a gazillion knives and he has this one video where he is showing off all of his hunting knives and puukkos. Maybe you have seen this guy. He never seems to show his face, but he speaks English with a foreign accent, like not as his primary language. He talks about dressing/ butchering game animals. Anyway, all of the knives in this video are "micro convexed" because he says it prevents chipping when you bump up against bone. So he's all about micro-convexing, like it's the best thing.

I was micro convexing before I heard of it because A.) I have always microbeveled my scandis and B.) I always did it free-handed, which always creates a slightly convexed edge.

I know there are purists who don't believe in micro bevelling of any kind, because certain knives have a single bevel to zero for a reason, and that's the way they should stay.

But, really? What advantage is there with the single bevel to zero? And if the micro convex prevents chipping, I would think it adds versatility.

BTW, I am not a "bush crafter." Not that I wouldn't want to learn those skills. I just never got around to it.

 

[Obsessed with Edges]

I'd think at some point, a 'convex' microbevel that's too small & too close to the apex would essentially be doing the same thing as simply wider geometry at the edge apex, if not just rounding it off. I very much like convexing the shoulders of edge bevels, mostly for the benefit of much-reduced friction in cutting thicker materials. But otherwise, I'd prefer not to deliberately attempt any convexing too close to the apex. When you get right down to it, a crisp apex still needs to be essentially a 'V' in order to cut well at all. Any gains in durability by trying to widen/thicken the steel by convexing too close to the apex will come at the expense of cutting performance, as I see it.

Sometimes it's difficult to figure out what a given individual actually means by 'microbevel' in the first place. The implications of it's impact on cutting performance may not be so bad, depending on what they view as 'micro'. Some might look at a secondary/tertiary bevel that's 1mm wide (convex or not), and call it 'micro', while others may view such a bevel as too big to be named as such.


David

 

[WRGreen]

On my knives, I've noticed that stropping will ever so slightly convex the edge bevel, and the extra smoothness gained seems to even out any angle inaccuracy on my part (I freehand sharpen w/ DMTs). Some of my sharpest knives have fully convex edges down to zero, and they've only ever been stropped for a crazy level of sharp. I think that the old adage "whatever works for you" may apply here, since there are so many variables involved. Cheers!

 

[redsquid2]

Thanks for the replies. If I find that video again, it may clarify exactly what the guy is referring to. I can't find it, but I think the youtube user name is "virtuovice."

 

[Sadden]

Depending on what the knife is being used for I can intentionally create some microconvexity. I have 2 main types of strops , Kanagaroo and Nanocloth.

The Nanocloth wont ever convex an edge.

The Kanagaroo wont if I just use it normally (as close to zero psi as possible) , However , if I start to use some pressure , say around 5 pounds or so , then it will create the tiniest amount of convexity right behind the edge of the edge. (Barely visible under the microscope) Im going to be doing some more testing to see if there is an increase in durability from this or not. But it would make sense if it did.

Normally on a pocket knife no I don't add any convexity at all.

Thinking of getting the WSKO with the 1x18" attachment and a bunch of linen belts. I already have all the CBN and Poly , would make doing large convex blades much easier. And cheap machetes.

 

[Obsessed with Edges]

(...) I was micro convexing before I heard of it because A.) I have always microbeveled my scandis and B.) I always did it free-handed, which always creates a slightly convexed edge. (...)

That's a good point to emphasize, and it's what I view as most important to understand. Any freehand sharpening will introduce at least some 'micro' convexity, and that's all that I generally feel is necessary. For me anyway, any deliberate attempt to force some convexity by altering my technique or stroke is just redundant, and usually results in more convex than I wanted anyway. It's better to let the human factor work like it does anyway, in freehand, and let the microconvex take care of itself. For me, the amount of convex can be varied more easily by altering the medium upon which the edge is created, i.e. a more conformable backing media will produce more convex, all other technique remaining unchanged.


David

 

[HeavyHanded]

I find if I am reasonably careful, the convexity from freehanding is spread out across the face of the bevel and not concentrated at the apex. For most tools I prefer not to have a micro-anything at the cutting edge, though there is frequently a tiny amount I suspect. Have looked at quite a few edges under magnification and don't usually see much if any. When doing big choppers like hatchets and machetes I imagine there is some, as I finish with a trailing stroke on a hard strop - difficult to manage precise angle control on larger cutters and hatchets where its a little more challenging to get a solid grip on the tool. In this case it probably helps to some extent, but due to how they get used would be tough to quantify.

Martin

 

[Allen R.]

I have watched a lot of virtuovoice's videos and I've learned a few thing from his videos, Like others said though when you freehand no matter how consistent you are you are going to get a slight convex. I just learned how to convex on stones and IMO, just sharpening to the best of MY ability then following up with stropping produces an edge that is 3 finger sticky, and I guess that would be considered a micro convex, but the proof is in the pudding , I am not satisfied with my edges until I can slice and or push cut toilet paper. FWIW I'm strictly free handing now and I'm getting edges way better than I could get with my Edge Pro, now is it because I'm convexing the edge and they cut better , or is is because my stones are better quality that I freehand with than I have for the edge pro? Who knows, I do know however , when I get a good coarse water stone my edge pro is gone.

 

[HwangJino]

My outdoor knife will get more aggressive convex while my folders and kitchen knives get very slight convex. My yanagi also gets convex. Only knife I don't convex (on purpose anyways) is my MLL scandi.

After years of sharpening my sushi knives I had to find edges that last but still sharp.
Each of my knives have their own level of convex depending on steel geometry and intended use.

LOVE seeing the light taper off the rounded bevel am I right?

 

[mtangent]

Sounds like the guy has been using too acute an angle for the circumstances, & a micro convex is his way of getting a tougher edge.