Convex edges: Are they really practical?

For big blades out in the woods, a medium-fine grit ceramic rod does great, convex or V edge. I don't know if the sharp maker lets you put the triangle ceramic rods into the hard plastic holder, but that would be a perfect setup. I bought one medium and one fine spyderco triangle ceramic rods from the sharp maker. I just bought the stones. They work very good freehand! I carry them in a hard case so they don't break. Thinking about just buying the kit though.
 
How long are you out in the field for? Months, years?

You can sharpen the edge the same way as you would any edge whilst 'in the field' and revive the unbroken convex bevel when you 'return'
 
Ok, it is true that freehand sharpening produces a convex edge.

That said I find convex edges are more difficult for me to sharpen because as I lay the edge flat on the stone and raise the blade over the shoulder I am not on the apex. Feeling the blade go over the shoulder as I lay it flat has a tactile feel making it easier for me to know when I’m on the edge.

With convex edges (such as on a crk) I find it quite abit harder to determine when I am hitting the apex.

A little advice for sharpening convex edge on a flat stone, use edge trailing strokes instead lf edge leading. That seems to help me abit. Usually this can help abit
 
Convex edge eventually happen if you free hand sharpen. It just takes a little practice to maintain that zero grind. The strop is key
 
Last edited:
In a real "survive now" situation, you won't have time to worry about the little details of getting a perfect edge, convex or whatever... you'll use the edge you have, "now", in order to survive, and make due with what you have be it to chop a log fir firewood, or chop through zombies... if/when you do find some down time, and you've "survived" the now factor, that's when you'll take/find time to address your equipment in detail, knife edge(s) included.

Example; in the infantry, all equipment is addressed before a mission or patrol. (Ammo'd up, fresh batteries, and edges sharp). When confronted with a real life "survive now" situation, nobody is stopping to sharpen their knife quick... if there is a break in action, then any issues are addressed, and yes, some would even pull out a field stone and sharpen a knife quick, if only for the soothing therapeutic value of sharpening a blade, but it's nowhere near the same intensity or exact detailed sharpening that one would spend time doing back in quarters at the F.O.B. with actual "down time".

But to answer the OP, in short, yes, convex edges are in fact quite practical, for all the reasons stated by others. And if you find yourself in a "survive now" situation, the last thing you will be worried about is sharpening your knife, if anything, you'll find yourself wishing you had sharpened it the day before...
 
marcinek said:
Mark the length of the edge with a Sharpie.
Click to expand...
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.
 
Last edited:
marcinek said:
....and cue the "convex has more material behind the edge" folks....
Click to expand...
That whole debate was moot and just got out of hand, because the argument for the more material behind the V edge was based on an infinite primary edge bevel. And the argument for the convex having more material behind the edge was based on there being a standard primary edge bevel coming off either a hollow or flat ground blade. Not a zero grind. Plus the nonsense about being able to assign a single numerical angle degree to a curved line...Technically both arguments were right and wrong at the same time. But i enjoy you bringing it up every chance you get marcy :)
 
Last edited:
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.
Click to expand...
It’s not the water taking the sharpie off.
 
When I sharpened free hand the edge always ends up a little concave, but I'm not very good at it.
 
Pilsner said:
It’s not the water taking the sharpie off.
Click to expand...
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
 
Last edited:
I've noticed a convex edge doesn't have as good edge retention as a V grind.

Tho a convex often better for reducing possible chipping if you don't know how to micro-bevel a V grind.

Easy to sharpen convex tho. Just youtube it for some visual tips. Mouse pad and sand paper is just a cheater way.
 
Mo2 said:
I've noticed a convex edge doesn't have as good edge retention as a V grind.

Tho a convex often better for reducing possible chipping if you don't know how to micro-bevel a V grind.

Easy to sharpen convex tho. Just youtube it for some visual tips. Mouse pad and sand paper is just a cheater way.
Click to expand...

Technically, if all else is equal, a convex should hold longer than a V grind vs. abrasive wear because the region behind that apex is thinner. It'll be more susceptible to plastic deformation, though.
 
FortyTwoBlades said:
Technically, if all else is equal, a convex should hold longer than a V grind vs. abrasive wear because the region behind that apex is thinner. It'll be more susceptible to plastic deformation, though.
Click to expand...
I mean I don't really disagree with that. I guess it depends on how it's sharpened and to what level. If I'm using a work sharp it doesn't last nearly as long as when I use my kme or edge pro and go up all the diamond stones and polish the edge a fair bit. But then take a look at say Michael Christy who freehand sharpens and goes for that maximum sharpness and puts it to the test cutting cardboard.

So maybe it's less about the difference between v and convex and how far from dull the knife is sharpened too.
 
In parts of the world where a machete is a man's livelihood, they are sharpened very quickly, regularly, with a stone. Most certainly not a V but not so convex as with a slack belt.
 
Even if a blade has a convex edge you don't have to use a mouse pad or a soft strop and try to follow or maintain that same convex grind ...

you can sharpen it as you would any other blade and you will just create a micro bevel that many convexed blades actual start with anyway ... so you can still achieve a nice sharp blade without using any special method.

but a convex is easy to maintain and as many have already stated if you're sharpening freehand you will end up with a somewhat convexed blade anyway ... just maybe not a high full convex.
 
Convex is easy to maintain. Just hit it on a strop! There comes a time when strops won't do the job anymore and you have to break out the stones. When you sharpen a convex edge on a stone, you're basically sharpening a flat spot on your edge. As a human factor, you can't maintain that same flat spot every time on every stroke, thus the "stairstepping" result. Stropping just blends all these "stairsteps" together. Once you get the muscle memory of how that knife glides across the stone, it will be second nature and it will be much easier to hold that same angle. The secret of it all, is being able to maintain that exact same angle on every push and pull stroke on the stone.
 
No, you can sharpen convexes on a stone using a rocking stroke that starts low and ends at the angle you want for the edge. It's really not that hard to do, and it doesn't create flats. But you only have to do that if doing cheek-shaping work after multiple sharpenings. It's really not necessary if freehanding. It's not going to make a super-pronounced convex, but freehanding inherently gives convex edges.
 
You must log in or register to reply here.
Back
Top