Convex sharpening on a diamond stone

awestib

awestib

Joined
Dec 29, 2008
Messages
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Today was my first real try of putting a convex edge on a knife with a diamond stone, so no soft backing. I have a larger camp knife made of 1080 steel. It has a about 6 1/2 inches long blade. Yesterday I cut down our Xmas tree (I know, it's been a while) in the backyard. The ground that I stood on was more gravel than anything else and I intentionally was not too carefull to not hit the ground, so I did hit some of the small stones. The edge looked horrible after so instead of putting a v edge on it, I tried to sharpen it on a diamond stone in a rocking motion. The result was actually not that bad, on the coarse stone anyway. I got a burr on both sides and wanted to carry on. Know however I switched to the good old soft backing and sandpaper to refine that all. I stropped at the end on leather. It was ok, still a few dents leftover and almost shaving.

Here is finally my question: you, that convex edges on a hard stone with the rocking motion, do you refine the edge on fine stones or do you do the same that I did and switch to sandpaper after the initial convex edge has been established? All other suggestions, tips, etc. welcome!

Andy
 
Usually I just finish on a fine stone, but it leaves a grind pattern that isn't very aesthetically pleasing, and I find it takes longer than finishing a straight bevel.

Seems like taking advantage of the rocking motion on a coarse stone could just lend itself to making the whole process faster, with using a soft backing still providing a more consistent mechanic to work with versus rocking on a hard surface.
 
"... Still providing a more consistent mechanic ..." exactly my thoughts too KennyB. The rocking motion works but seems to be "inaccurate" - for me anyway. it's a whole new ball game!
 
like kenny said if you finish with a hard stone like fine diamond or india, your bevel will look like crap. if that's important for you the solution is a softish waterstone like naniwa SS that will help blending the facets together.
 
I have a Falkniven combination stone that ceramic and 25 micron fine grit diamond. They recommend using a circular motion. It works very well.
 
I use sort of back and forth scrubbing motion, start with the spine low and slowly elevate till I reach the apex - overlap the length of the blade. I raise a burr, remove the burr etc just as with a V bevel. I do not attempt to rock the spine through a full arc with each pass. If you overlap low to high the grind marks are a lot less evident. Then I'll strop with some black compound (Sears) on five or six layers of newspaper, avoiding the apex (sometimes use a Sharpie to see that I'm not hitting the edge). This should smooth things out visually pretty well. Then I hit the apex very lightly with a finishing stone. If its a chopper (largish knife, machete, hatchet) I'll just use the black compound and follow with some white (Sears), hitting the entire grind area all the way to the apex. Only on my smaller knives do I intentionally keep the edge toothy, stropping with nothing more aggressive than plain newspaper.
 
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