Many of my knives are ground with convex edges. This is different than the hollow or flat grinds that you find on most knives and they must be sharpened and maintained a bit differently.
Insert grind pics here;
Most knives have a Primary bevel that goes almost to the edge and then a small Secondary bevel that forms the cutting edge. The secondary bevel is flat and can be sharpened on hard stones, or more often, on machines.
Convex Edges have two smooth arcing surfaces that meet at the cutting edge without a bevel. These edges can only be made by hand, which is why the vast majority of knives don’t have them. This design has many advantages.
The first advantage is that there are no leverage points on the edges of the bevels to stick in bone or wood. Those little corners between the bevels don't look like much, but they will wedge tightly into wood, especially if they are twisted. This is one of the reasons that axes are ground with convex edges; so they don’t stick. Nearly any knife can cut open a deer or an apple, but cutting wood is a much more demanding task outdoors and my knives will excel at it. You can also think of it like aerodynamics, the smoother, rounder surfaces pass more easily through the air than faceted or flat surfaces, and so it is with knives through solid materials. Ever see any hard lines on a fish or a bird? Me either, it's inefficient.
The next big advantage is in the strength of the edge. All other things being equal, there is simply more metal supporting the edge on a convex knife. Numbers vary, but it is as much as 45% more metal than on a hollow ground knife. That translates to strength.
The third advantage is that they are cheaper and easier to maintain. You just have to learn how it’s done. Please do not use stones, grinding wheels, or pass thru type sharpeners!!!
There are two parts to this tale; Sharpening and polishing. Both stages are done on a strop. I prefer a paddle or block style strop. I have some for sale on the site, or you can easily make your own with a block of wood, leather, glue and the appropriate compounds.
A full sharpening should rarely be needed, but stropping regularly is the very best way to keep your knife in razor sharp condition. Doing this after use will realign the fine edge of the blade and prevent it from being broken or rounded over. One of the advantages of the high carbon steels that I forge, versus many modern stainless steels is the flexibility of the fine edge. Added alloys tend to make the fine edge crumble, requiring a regrinding to sharpen. Carbon steels are more flexible and while they may bend at those ultra fine levels, they do not crumble and can easily be realigned with these techniques.
To strop your knife, begin on the course compound on the leather paddle or block ( it’s often grey). Lay your knife on its side and draw the life smoothly backwards, AWAY from the cutting edge with medium pressure. Make sure to roll the spine of the knife up until you are just polishing the edge of the blade. A bit of ink from a sharpie marker on the edge can help show where you are making contact. Mark your whole edge black and wipe along the strop until the black on the cutting edge is worn away. Be cautious of raising the knife too high as it will round the edge, but too low and you will simply polish the side of the blade, so err low at first. Raise the butt of the knife as you round the belly of the blade and get to the point, so you don't wear it away. Strop until you have a nice even polished edge on both sides. Put the blade in good light and you will be surprised how well you can see the dull spots. Use grey compound first, then green, then bare leather, if you are feeling dangerous. Be sure to clean the blade between grits or you will contaminate the next compound. At this point your knife will have a mirror polish and will look pretty frightening. It should easily shave the hair off anyone brave enough to sit still for it. It the closest most of us will get to a lightsaber. By the way, because the edge is polished, stropped knives do not feel as tacky sharp as an unstropped knife, but they will cut far better. This is because you are usually feeling the rough burr of broken down metal on the edge and that is not durable. Stropping removes the burr and polishes the edge, resulting in a much more durable edge. Be careful, and remember, a knife is not truly yours until it has drawn your blood. Stropping your knife lightly after each use should keep your edge in useable condition for a very long time without having to resharpen.
Is something you should rarely, if ever, have to do. It involves reshaping the edge after major damage or wear. The gist of the method is to use wet and dry sandpaper on an ALMOST hard surface like leather (the strop). Lay the wet and dry paper on the leather and swipe the knife at a low angel AWAY from the cutting edge with medium pressure. It will take a little practice to get the feel of keeping the right angle. Be careful not to raise the spine of the knife too much, or you will dull it ( too low is no big deal, so err low at first ). Just match the curve of the side of the blade and then tip up a hair to keep the polishing right on the edge. You can use a Sharpie marker to darken the metal on the cutting edge to make it easier to see the scratch marks.
To resharpen a dull knife, start with 400 grit wet and dry paper and move to 1000 grit. Use even strokes on both sides until the edge comes together in a burr. Once you have an even burr on the 1000 grit, you can move to the compounds on the strop, as described above, to get a razor edge. Don't forget to raise the handle of the knife as you round the belly and head for the tip of the blade, or you can easily wear the tip too thin. These grits of W/D paper wear out pretty quickly, so don't waste your time rubbing on dull abrasive. A sharp, fast cutting action will give you the best and most accurate edge.
I prefer to use high carbon steel in my blades. I feel that the increase in performance over the stainless steels, as well as the forging techniques that they allow, is worth the minimal maintenance that they require. They are prone to rust, however, and should be kept dry when not in use and never stored in a wet leather sheath. A light coat of oil will keep your blade nice and shiny. Nearly any oil will do, but I prefer camellia oil, since it is natural and non toxic and it won't make your apple taste like W-D 40. If and when you get some rust on the blade, do not freak out. It has no practical effect on the knife (unless it's deep pitting). Carbon steels tend to develop a wonderful grey patina over the years that looks great and helps prevent more rust. Get yourself some fine steel wool, or better yet, the synthetic stuff and scrub the rust off. Scrub the whole blade (except the cutting edge) so the buff marks are even, if you care. Scotchbrite pads work well too. Wax or silicone can be useful if you are putting the knife into storage for a long time, especially if you have high humidity in your area.