Convex edges: Are they really practical?

When I freehand, I try my best to hold a consistent angle, so I guess I strive to sharpen to a V edge. Stropping on it over time will eventually convex it.
 
You have to be careful to modulate you pressure and angle to get a consistent angle on a strop, though. It's very easy to accidentally broaden your edge angle when using a flexible backing.
 
extrastout said:
this doesn't really work on water stones....comes off quickly from..... water, and it's really hard to see the sharpie on a shiny rounded convex. I think your best bet is to listen and feel for the edge making contact with the stone, then work the edge. I start sharpening behind the edge and then catch the edge at the end of the sharpening stroke. You can find the angle by pushing the blade forward lightly on the stone or strop. Keep bringing the angle up until the blade catches. Thats your edge.
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That works fine, provided your edge isn’t so rounded it doesn’t catch.
 
FortyTwoBlades said:
You have to be careful to modulate you pressure and angle to get a consistent angle on a strop, though. It's very easy to accidentally broaden your edge angle when using a flexible backing.
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True this. Leather comes in all thicknesses and plush levels. With the more plush leather, I tend to lower my spine a hair more, than stropping on thin stiff leather, or on bare balsa wood. Nowadays, I try and focus on holding a steady angle and replicating the same motion on each stroke.
 
Easier to hit an apex on a "V" as opposed to on a "U" . In a field or in your room it don't matter.
 
extrastout said:
when your chasing the edge on a smooth convex, a sharpie wears off before you find it. The water and material removed from the blade while trying to pinpoint that edge, makes short work of it.....I found sharpies are good for chasing the edge not finding it on a CONVEX, you cant pinpoint a convex edge with a sharpie. This techinique works on a toothy V EDGE in my opinion. Convex is rounded, its all about the feel and follow through technique for me...unless you use a mousepad and paper, which I don't

In the field, it sucks if you can't sharpen your blade because no one brought a sharpie....OP doesn't want to bring out a mousepad either
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Well, that goes without saying but fair enough. I think Marcinek was responding to another member discussing difficulties when sharpening convex in general, as opposed to when out and about specifically.

I’m pretty certain he wasn’t suggesting that one always needed a Sharpie to get an edge. :thumbsup:
 
The biggest disadvantage of a convex edge is that you have more metal to take off in each sharpening, which takes more time. Of course, you could just sharpen the apex and do a full blade thinning every once in a while to restore the original geometry, like you would on a ffg.

I have no problem doing a full sharpening in the field on a regular stone, but it does take more time. There is no noticable difference in performance when everything else is equal (like the thickness behind the edge, etc). I wouldn't bother unless you like to challenge your sharpening skills and experiment with different types of blade grinds. You could start noticing a difference when using heavy chopping tools like large knives and axes.
 
I have a Spyderco Forester that literally used to have an apple seed shaped bevel. I liked it but it had a habit of bouncing off rather than biting in when used as a camp chopper

A couple of years ago, after some very patient, careful & repeated sharpie marking and light dremmel flapper wheel sanding it has a much lower profile (right term?) and much better bite when chopping and batoning while camping in the summer & cutting pizza at home in the winter.

It's not nearly as good looking as it used to be but i didn't buy it for looks (for the most part) might have to send off to someone for a very light re-grind just to improve the aesthetics.
 
Very good information here.

Preference for or against a convex grind or edge depends on intended uses. For uses that are more like an axe, such as chopping wood, splitting wood, limbing and the like - convex woks great and seems to support the edge more against chipping or folding. For slicing a ripe tomatoe or a phone book page, less is better at the edge - at the expense, of course, of folding or chipping when rougher use is encountered.

A convex edge with a flat or "V" micro bevel seems to be what my amateur self gets when using a bench stone or guided sharpening method as opposed to free-handing where, again, my amateur self usually winds up with a flat-ish or V-ish convex edge.

In all, either, both or all three (is that grammerically correct?) will work - just depends on how thin the very edge is and how durable/rugged you want it to be.
 
Sergeua said:
New users of a sebenza will disagree
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How, exactly, would it be more difficult to hit the apex on a convex? Any angle of approach less than that of a V edge will result in the wear being born directly by the edge shoulder. Please explain your reasoning.
 
FortyTwoBlades said:
Nope. If anything, a convex is faster and easier to maintain than a flat edge of equal angle (in the context of field touch-ups) because it's going to be easier to hit just the apex. Think of a convex as being like a series of grinds that decrease in angle as they move back from the edge. Your stone will only be sharpening (rather than shaping) if it's hitting the apex, and even the slightest bit too shallow on a flat means you're contacting the shoulder rather than the apex. On a convex, that shoulder has already been ground off and your contact point is more likely to be pretty close to the edge where the abrasion may work down to the apex itself and then cause actual sharpening abrasion. Freehand sharpening in general is not going to be perfectly flat, so you're already making a convex.
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Sounds to me like you are comparing putting a microbevel on a convex in the field vs trying to sharpen a V edge without a micro. Let's compare microbevel on convex vs micro on a V edge. The answer is an obvious one.

Maybe i somehow missunderstand your post?
974887.gif

Its almost as if you are comparing picture on the far left with the one on the far right. But what i say is take that picture on the far ^right ^ and draw a V inside of it. ( Connect 3 corners with straight lines). Now let's compare...

A convex edge has more meat behind the apex (that's the whole point of having one) so before i get to the shoulder of a V there are already plenty of the compound grinds on a convex that get in the way.
xv0b6t1h.jpg
 
Sergeua said:
Sounds to me like you are comparing putting a microbevel on a convex in the field vs trying to sharpen a V edge without a micro. Let's compare microbevel on convex vs micro on a V edge. The answer is an obvious one.

Maybe i somehow missunderstand your post?
974887.gif

Its almost as if you are comparing picture on the far left with the one on the far right. But what i say is take that picture on the far ^right ^ and draw a V inside of it. ( Connect 3 corners with straight lines). Now let's compare...

A convex edge has more meat behind the apex (that's the whole point of having one) so before i get to the shoulder of a V there are already plenty of the compound grinds on a convex that get in the way.
xv0b6t1h.jpg
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Nope nope nope. I'll let marcinek handle this one, though. :D
 
Also, that argument has nothing to do with the ease of hitting the apex.
 
If we are talking about a zero convex grind, then there really are very few more simple things to accomplish using freehand sharpening. Is it a case that because it requires a different sensibility to achieve, a different motor skill, that it is somehow intimidating?

I genuinely don’t get it. I spent ten days in a forest in France last year, with a Fallkniven A1 that I had at zero convex. I had no issues maintaining that edge, none. This was with a Lansky Puck. And, I reiterate, I’m not fit to compete with some of the beautiful, polished edges one sees on this forum. But this thread is about practicality, not hair whittling.

I guess, tautologically, it isn’t practical if you can’t do it. But I would encourage members to give it a try: don’t be shy!
 
FortyTwoBlades said:
Nope. If anything, a convex is faster and easier to maintain than a flat edge of equal angle (in the context of field touch-ups) because it's going to be easier to hit just the apex.
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ditto
all you have to do is strop the convex edge on a palm sized leather strop pre-loaded with sharpening compound (or even back of the leather belt that has some compound on it will do) and your knife will be sharper longer than you will be able to survive in the wild ;)
 
Sergeua said:
Easier to hit an apex on a "V" as opposed to on a "U" . In a field or in your room it don't matter.
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maybe I never had a truly dull blade...I can find the apex on my user at home beater axe. On a dull convex blade you should catch the apex of where the convex start to dull/flatten. This is where I figure you start working the edge until you make it the the true apex. The weird thing about a convex edge, is it can feel dull on your finger but slice right through newspaper.....maybe its not even dull and all you have to do is use it:eek:
 
ridnovir said:
ditto
all you have to do is strop the convex edge on a palm sized leather strop pre-loaded with sharpening compound (or even back of the leather belt that has some compound on it will do) and your knife will be sharper longer than you will be able to survive in the wild ;)
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Or if the damage/wear is too much for a strop, just touch up the apex with a conventional stone and don't even worry about hitting the whole face of the bevel. Just lay the cheek of the bevel against the stone and lower the edge until it just contacts the stone.
 
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