The final sharpening thread (help me)

Hey folks, remember his question specifically relates to (1) sharpening a CONVEX EDGE (2) IN THE FIELD.

I think you've got 2 basic choices. First, you could take the lessons from the two convex sharpening tutorials that others have provided links for and adapt them to the field. In other words, glue a piece of leather or mousepad to a smallish piece of wood, say 2" x 6", and take along strips of 320, 600, 1200 and 2000 wet and dry paper. The leather/mousepad sandpaper method does work and with practice you'll get great results. No big magic bullet secrets there -- you just learn the right pressure and angle after a lot of practice.

The other option is to use a regular stone as you would on a non-convex edge. For example, get a small whetstone or diamond hone to take into the field. Sure, this slightly changes the convexity of the edge, but you can restore that when you do your next at home convexing session. Again, there's not a boatload of secrets that haven't been covered ad nauseum on this forum and elsewhere. For this type of sharpening most of it boils down to finding the right angle and using a few very light strokes at the end at less-accute angle to cut off any burr.

On the at-home-convexing subject, I just got a cheap belt sander, and it's loads easier to sharpen a convex edge with one.
 
Learning to sharpen is often a journey of self discovery that can last decades. I know I still learn from others and adapt/modify my methodologies, s I have done since the 1960s. In some ways, I don't think I really "got it" for many hundreds/thousands of strokes. There are numerous videos and written tutorials. Unless you have someone physically showing you and guiding your hand, they are the next best thing.

As to convex, another option is rubber sanding blocks (auto parts store) and instead of moving the blade, move the medium. Perhaps the biggest hurdle for many is removing that wire, or feather edge without fracturing what supports it and having to start all over again.

One neat thing I read here years ago and have still not tried is simply tacking up a sanding belt to a vertical surface and wiping in an edge. it sounded like it would work a charm for those frustrated with regrinding a convex edge at home. I thnk what throws many off is the concept of working the whole grind, if the edge is really gone.

Something else mentioned earlier in this thread is quite true. If you are not using a guide and sharpening free hand, your beveled edges wil often be a little convex and blended.

I tend to use small stones and sticks along an edge, as much as across it. As many of my edges are more than thirty inches (swords), I find it easy to blend beveled edges this way and tune convex edges nicely, without imposing more than a micro-bevel. A traditional polisher of Japanese swords will be using quite flat stones to both form and polish (resulting in sharpness) convex grinds.

Just for yucks, if you are not familiar, Google Hybrid Polishing and read Antonio's (Blade Design) article that was prompted by someone here in the states doing JApanese style blades in a non-traditional manner.

Practice, practice, read, watch videos, practice. Repeat as needed and always watch for what you are missing, or might yet learn from others. I know I still learn. I started with knives and axes in the sixties.

Cheers

Hotspur; anyone have a running count on sharpening threads here/
 
I should have mentioned earlier that I carry a broken bit of a ceramic 'crock stick' type sharpener with me sometimes when trapping. This is just a round rod of ceramic material. I use this like a steel, or sometimes like a file, to touch up my knife edge.
 
Hey, the idea of moving the abrasive got me thinking, what about taking strips of wet/dry paper or narrow sanding belts and sort of "shoeshining" them across each side of the edge (spine-to-edge movement only) at a narrow angle? The knife would have to be immobilized, of course. Perhaps the handle could be temporarily lashed to a tree or held between a boot and a rock. Not much pressure would be necessary to touch up the edge, so deflection would be minimized.
 
I have solved this problem for some years ago.

I have also told about it here many times - and no one here seams to understand it !? It is very simple to do. I try to explain this - a last time.

1. A straight guide rod guides the sharpener to go straight and the result is a straight edge.
2. A slightly bended guide rod guides the sharpener to make a curve across the edge = the edge gets convex.
3. The guide rod slides thru a fixed point in the back end. The height of this point decide the convex curve (steep or flat).
4. I have solved the principle as in the picture below. A screw with a loop gives me the possibilities to, in very small steps, decide the convex curve (or sharpening angles when I use a straight guide rod). The screw can adjust the sharpening angle in 15/100 parts of 1 degree = half a turn. 3 full turns is 1 degree.

bs1019cdn8.jpg

Shot at 2007-09-19

Look at this picture, think about how the sharpener moves when you slide it across the edge. The bend on the guide rod lifts up the back end of the sharpener more and more when you move the sharpener forwards. The movement across the edge make the same curve every strike you do. = you get a perfect convex edge, you sharpen with 100% control of the curve and you take away very small amount of material from the edge.

If you, as I recommend, sharpen your knife before it gets dull, you just “polishing” the edge with a very fine ceramic sharpener, that’s all you need to do. This take about 10 seconds to do.
Every sharpening (polishing) is a maintaining of the first grinding/sharpening you did becous the angle is the same. If you follow this, you never, with normal use of the knife, need to grind the knife again, at least in many years.

It is the simplest things who is the hardest to solve. This is a extreme simple solution, on a very old problem - just bend the guide rod slightly. Can it be simpler? And it works perfect!

And yes, it is protected.

Thomas
 
KeithAM said:
The other option is to use a regular stone as you would on a non-convex edge. For example, get a small whetstone or diamond hone to take into the field. Sure, this slightly changes the convexity of the edge, but you can restore that when you do your next at home convexing session. Again, there's not a boatload of secrets that haven't been covered ad nauseum on this forum and elsewhere. For this type of sharpening most of it boils down to finding the right angle and using a few very light strokes at the end at less-accute angle to cut off any burr.
Click to expand...
IMO that's excellent advice. I personally like about a 4" long stone for freehand sharpening, but the operation is no different. A big advantage of using a stone rather than abrasive paper is that paper can curl or roll where the edge contacts it and prevent you from ever getting the edge sharp. With a stone you can use more pressure to repair a badly blunted or damaged edge quickly, lightening up as you approach your final sharpness, and essentially have complete control. It's an invaluable skill, really ... once you've got it down, you've pretty much mastered the basic mechanics and principles of sharpening which apply to whatever other sharpening system(s) you decide to use.
 
You must log in or register to reply here.
Back
Top