Convex Edge Vs. Stropping

[Gunsnknives]

My understanding is that a convex edge can be made by essentially stropping the blade back on forth on an abrasive surface with a soft backing (like a mouse pad). Convex edges can also be made by sharpening a blade on a hard "stone" if the blade is free-hand sharpened (since the variation of the angle during free hand sharpening applies a natural convex).

Is the difference simply the angle at which the cutting edge is stropped/sharpened and they are technically the same thing? Or perhaps I'm missing something important.

Thanks!

 

[richard j]

a convex edge done on a soft backing is going to be more even and uniform where one done on a stone is not going to be as uniform. up around the belly to the tip is going to be more uneven due to the curve of the belly making it hard to convex the edge uniformly.

 

[Georgia Guy]

Just a question not to say one is better than the other, I have never used a convex edge. If you have a convex edge you have to pack a piece of a mouse pad, some sand paper into a small tin to resharpen your blade in the field, right? If you have a traditional edge all you need to do is throw a very small one hand ceramic type sharpened into your kit. One takes up less space and is much lighter than the other. In a pinch you could use a brick to resharpen a flat grind, so why the big deal over convex? Not trying to insult a convex purist just something I have been curious about.

 

[richard j]

if i were to take one of the convexed edge knives i make out in the field, i would only take a 400 grit jflex belt and some polishing compound to rub on the backside of the belt and use it as a strop. the belt can be hooked over a tree and you would either strop the blade or work up a burr and then strop the blade. the belt can be rolled up into a small enough roll to fit in a small package or your pocket.

 

[Obsessed with Edges]

You don't 'have to' use a mouse pad to maintain a convex. Any soft(ish) backing will do. I've been doing a lot of convexing (both making convex edges and touching up) using a simple paper catalog/magazine. The nice thing about doing it this way, you can regulate how 'soft' the backing is, simply by increasing or reducing the number of stacked pages under your sandpaper. And for light maintenance, you don't even need the sandpaper. Just your compound of choice, applied to the paper itself, works great for stropping.

You can also make a leather 'hone', sized exactly the same as any other hard hone you'd use for a V-bevel. Pocket size, bench size, or anything in between. Just a piece of wood with some leather on it, and a small strip (or a variety of strips) of sandpaper, or a tube of polishing paste or compound. It can be made as compact & portable as you want.

And in the field, for camping/hunting/etc., you could even use compound applied to the inside of your leather belt. Better yet, multiple grits applied in sections of the belt. Coarse, medium, fine and bare stropping, in a 'hone' that you wear around your waist. Doesn't get any more portable than that!

Possibilities are limitless. This is why I do believe it's every bit as easy, maybe more so, to maintain a convex.

 

[Georgia Guy]

I guess you just have to love a convex to go through all that. I am all about simple though. Maybe I am just ingorant to the benefits of having a rubbing compound inside my belt while hiking. As I stated earlier though I have never messed with one done right, maybe that is why I don't get it.

 

[Obsessed with Edges]

I guess you just have to love a convex to go through all that. I am all about simple though. Maybe I am just ingorant to the benefits of having a rubbing compound inside my belt while hiking. As I stated earlier though I have never messed with one done right, maybe that is why I don't get it.

The 'compound inside the belt' is something that I haven't actually done yet. BUT, the thought has crossed my mind more than once. I just recently purchased some new belts, and the leather quality seemed quite good. So, naturally, my mind drifted to using one as a strop. Then, of course, with all that length available, the idea of a 'sectioned' multiple-grit strop occurred to me. This is the thought process of a truly obsessed sharpening fanatic, I know.

The more things I've tried, the more I've realized how simple it can be to achieve the same ends. Some of these ideas may seem convoluted or too much trouble initially. But, giving different methods & tricks a go can really change the way one thinks about it all. Really opens up the box o' possibilities.

Regarding the significant differences of a convex edge, the thing I like about 'em is how 'smooth' the cutting gets in deeper & tougher material. Round off the 'shoulders' of the bevel, and the cutting friction really drops off. That's what I like the most about convexing. The strong 'arch' of a convex seems to really help an edge last, too. Very durable, even noticeable on small pocketknives with thin blades. Edges don't roll nearly as easily, on a convex.

 

[Gunsnknives]

Thanks guys for all the info on sharpening. I'm still learning. Thanks to the moderator to moving me to the right forum.

So...to answer my original question, stropping and making a convex edge seems basically the same thing? I guess technically if you perfect stropping, you actually won't round the edge, but free hand stropping will.

I have also "over stropped" my edge meaning I probably put too obtuse and angle on the cutting edge.

 

[HeavyHanded]

Just a question not to say one is better than the other, I have never used a convex edge. If you have a convex edge you have to pack a piece of a mouse pad, some sand paper into a small tin to resharpen your blade in the field, right? If you have a traditional edge all you need to do is throw a very small one hand ceramic type sharpened into your kit. One takes up less space and is much lighter than the other. In a pinch you could use a brick to resharpen a flat grind, so why the big deal over convex? Not trying to insult a convex purist just something I have been curious about.

One can make a very nice and effective convex edge on a hard stone - maintenance with the same hard stone or a small diamond stone/card, etc is every bit as easy as using sandpaper or any other method. There are very real benefits to the convex edge profile, esp when used on thicker blades and hatchets, but noticeable on thin blades as well.

 

[Obsessed with Edges]

Thanks guys for all the info on sharpening. I'm still learning. Thanks to the moderator to moving me to the right forum.

So...to answer my original question, stropping and making a convex edge seems basically the same thing? I guess technically if you perfect stropping, you actually won't round the edge, but free hand stropping will.

I have also "over stropped" my edge meaning I probably put too obtuse and angle on the cutting edge.

Stropping will usually add at least a little bit of convex to any edge, IF done on any surface that's even a little bit soft, or if done free-hand. The degree of convex depends on how soft the backing is, and how much control one maintains over the angle and pressure. If one were to strop using a guided jig of some kind, on a very hard backing, that would certainly minimize the convexing effect.

And 'over-stropping' usually rounds off the edge, either by pressing too hard or by simply going too far at a steeper angle. You can strop at a higher-than-normal angle to break off a burr, for example. But, great care needs to be taken to do it at extremely light pressure, to minimize rounding the edge.

 

[Gunsnknives]

Stropping will usually add at least a little bit of convex to any edge, IF done on any surface that's even a little bit soft, or if done free-hand. The degree of convex depends on how soft the backing is, and how much control one maintains over the angle and pressure. If one were to strop using a guided jig of some kind, on a very hard backing, that would certainly minimize the convexing effect.

And 'over-stropping' usually rounds off the edge, either by pressing too hard or by simply going too far at a steeper angle. You can strop at a higher-than-normal angle to break off a burr, for example. But, great care needs to be taken to do it at extremely light pressure, to minimize rounding the edge.

Thank you, makes sense.

Regarding the significant differences of a convex edge, the thing I like about 'em is how 'smooth' the cutting gets in deeper & tougher material. Round off the 'shoulders' of the bevel, and the cutting friction really drops off. That's what I like the most about convexing. The strong 'arch' of a convex seems to really help an edge last, too. Very durable, even noticeable on small pocketknives with thin blades. Edges don't roll nearly as easily, on a convex.

I think I'm liking this idea of convexing more and more. I have to be careful not to round of the cutting edge though! I think I'm might spend a bit more time "stropping/convexing" at a shallower angle than the cutting edge to round off the shoulders just a bit (and to prevent round off the cutting edge). I also hope to test the edge longevity.

Thanks folks!

 

[db]

You can maintain a convex edge just as easy with a hard hone as a soft one. No need for anything special. You shouldn't be regrinding the edge profile to maintain it, a stroke or two and that is about all it takes. Heck I use a very fine round ceramic rod to maintain my convex knives all the time. I even have heard of people useing a paper wheel to maintain, and finish a convex edge. And a wheel is the opposite shape concave as a convex grind. The biggest problem I had with stropping was the same as most. I rounded off the edge. It is surprising how easy it happens. Keep the angle shallow and the pressure very light. It really doesn't take much to finish an edge on a strop.

 

[mdc5162]

Both are easy to maintain in the field if you know what your doing. There is a video of someone making a paper cutting sharp convex edge with a piece of 320 grit sandpaper. Its all skill and knowledge. So if you like convex you can do it, if you like V grinds you can do it. I think its mostly preference but convex takes a tad bit more effort to learn.

I guess you just have to love a convex to go through all that. I am all about simple though. Maybe I am just ingorant to the benefits of having a rubbing compound inside my belt while hiking. As I stated earlier though I have never messed with one done right, maybe that is why I don't get it.

 

[UnknownVT]

I had an old thread that discussed convex edges -

Convexed Edge (link)

It's fairly easy to see the common single bevel - although can be sharp at the actual edge - presents a hard discontinuous shoulder at the face, resistance when cutting through things.

More sophisticated sharpening sometimes sets a secondary or transition bevel - this improves things - one can obviously do more transition/intermediate bevels to improve the cutting through ability -

but ultimately with enough transition angles/bevels one basically ends up with a convex edge.

I'm no a purist - but have honed freehand for years using a fine EZE lap diamond hone which removes metal pretty quickly and does not leave too coarse a finish - I then use a loaded leather strop (I think it's jeweler's rouge - but it looks like a piece of white chalk). But because I realize I am not consistent - I then actually use a 22.5deg V-hone round crock stick very lightly to set my final edge -
- then in idle moments I strop on a piece of cardboard -

this was a piece handed out by Ken Warner (editor of Knives 'xx for years)

In the field where compact and lightness is a premium - I would carry a short (4") fine ceramic round rod (failing that I'd just use the unglazed bottom of a mug or plate) and a piece of cardboard (or just find one). The ceramic rod probably can hone set almost any edge unless really dull to begin with - the cardboard can strop to a good finish and maintain a convex edge.

To start it's probably worth buying a convex edge knife than to modify a non-convex one.
Get one that is zero bevel - ie: does not have a separate bevel for the edge - the face continues into the edge.
Ken Warner Knives has both a folder (BGG) and fixed blade (SGG) that are relatively affordable -
the BlackJack Small - Kraton handle is still available as low as $25 shipped and is a great value for a zero-bevel convex knife (it is a bit thick - but makes up for it by the great convex edge - Review - BlackJack Small Comparison )
for prices do a google shopping search.

Hope that helps

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Vincent

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