How do I convex a v-grind?

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Pietje010

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Dec 30, 2005
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I want to learn putting on a convex edge bevel on a factory stock v-grind bevel, on primary flat blades. Its especially for a Becker Knife and Tool Combat-Utility BK7 and later one a Howling rat. Does anyone have any good links or tips?

Afther some surfing i only found
- http://home.nycap.rr.com/sosak/convex.htm
 
That's the one I learned from. I don't know how/if you should modify it for a large knife.
 
I find that a compound bevel (two v-bevels) is at least as effective as a convex bevel, and much easier to maintain.

Typical compound bevel might be:
- A main bevel of 20 degrees included (10 degrees per side).
- A micro-bevel of 30 degrees included (15 degrees per side).

If the edge is not strong enough (rolls or chips), just increase the micro-bevel to 35 or 40 degrees - whatever it takes to strengthen the edge for cutting harder materials.

Maintainance of such an edge consists only of re-honing of the very narrow micro-bevel - very little metal-removal required, very quickly done. I typically use the little 1" X 5" Spyderco DoubleStuff hone for touching up the micro-bevel on my blades.

If that's not 'convex' enough for you - just hone or strop away the little shoulder between the main and micro-bevels. Voila - convex bevel.
 
Cliff Stamp said:
What exactly are you trying to achieve with the grind modification?/QUOTE]

A blade whit a edge that stays sharper for longer time and can be easer to maintenance in the field. But are these real results? I’m a total nood on regrinding.
Click to expand...
 
If you hand sharpen without the use of any type of jig you will put a convex edge on. I use a coarse bench stone to do this, then finish with what ever grit/ finish you like for an edge.
 
Pietje010 said:
A blade whit a edge that stays sharper for longer time and can be easer to maintenance in the field. But are these real results?
Click to expand...

Generally no, there is a massive amount of hype about the convex edge, most of it is radically misleading. Generally most knives will benefit from a relief grind, this just means a more acute bevel which is usually not taken right to the very edge. The BK7 and Howling rat come with an initial primary edge of about 15-20 degrees per side and thus if you sharpen at about 10 degrees per side you will increase the cutting ability and ease of resharpening by reducing the width of the factory bevel. Depending on how hard you plan to use the knife you reduce the primary edge accordingly. If you are just cutting and chopping then you would apply the relief grind pretty much right to the edge and then sharpen at about 15 degrees to apply a micro-bevel. For heavier work like batoning you would leave the primary edge a fraction of a mm wide to insure it didn't roll on chisel cutting harder knots.

-Cliff
 
I never planned to apply two bevels on the edge, just because i expected to maintain one angle hard enough so i can´t bear a second.;)

One or the other method leads two similar results i supose. The half convex method is a nice thing. The mouse pad method is pretty easy and relative failsafe. A sligth touch up with a ceramic rod to finish the sharpening session and later on is enough.

On new knifes or knifes with thick edges a little help from a professional knife sharpener might make sense. But don´t twist a prof with someone who just takes money for the job.

By form and personal feeling the edges seem to be a bit stronger than before. But they do not get that amazing sharpness like V edges can get.
 
I’m starting to think of not applying a convex edge on my BK7. But I’m practising on a Opinel no8 to control the technique and to test the results. It’s just not handy enough to grind away a V for a convex for the small benefits and eventually damage the blade.
 
With edges it isn't a matter of convex vs v-grind as much as it is edge thickness and angle. Many knives can benefit from a relief grind which is just a lower angle applied to the edge to make the very edge easier to sharpen. The angle of this lower edge like the primary edge will depend on the steel and the use of the knife, but typically it is *much* less, like half.

-Cliff
 
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