In one of my previous articles, I briefly touched on sharpening this type knife, but I wanted to get into greater detail so others can replicate this process, if they desire.
After shaping the blade with different tools, it looks like a knife in form, but is still just as thick at what will be the cutting edge, as it is at the spine. At this point I head to my Baldor 1725 rpm grinder and remove material on both sides of the blade, as opposed to a knife that only has a bevel on one side, while the other side stays flat.
When it comes off of the grinder, it can cut you if you were to run your finger along the blade, but it is not a useful sharp, in my opinion. The grinding wheel is round, and as the side of the blade has metal removed by the wheel, the shape is called a hollow grind. If you can imagine if you were to take a block of clay and press it against a static grinding wheel, when you pull it away you’d see a curved surface. This is ultimately what happens as you present the knife to the grinder, even though it takes more time to take on this shape, as the wheels must gradually abrade away the metal. Sorry if this part is getting too deep, as I just want to make sure you understand the shape of the knife’s cutting edge. On to the “good” part.
With the hollow grind shape, when you want to sharpen the cutting edge, the base of the bevel works with you to make it easier to know you are working at the correct angle. When you put a flat surface (similar to a ruler) up against the bevel, you can feel when both the cutting edge and base of the bevel are both touching. If you had a flat bevel or a convex bevel from the base to the cutting edge, it can be very difficult to actually feel that you are in correct alignment, especially when the bevel is very small.
When I begin to sharpen, immediately after grinding, I use my Dia-Fold diamond sharpening hone. I’ve owned this for 20+ years, and it started out as a Coarse hone, but over the years the diamonds have worn somewhat, and I believe it is now more in the Fine range of grits. If I had to try to pin down a specific grit, I’d see it as similar to a 1000-grit stone. I hold the blade in one hand and the Dia-Fold in the other, and feel for the hone to touch the two high areas, the cutting edge and the base of the bevel. With it correctly in position, I slide it down the knife until I reach the end of the cutting surface. I try to keep it consistent, by working each side in an alternating pattern, but you can also just work each side the same number of strokes, which will provide a similar result. When the knife comes off of the grinding wheel, I can tell when it is finished by the burr along one side of the cutting edge. This burr can be fairly significant from the grinder, so besides working with the first hone until both sides show signs of the grit all the way to the cutting edge, you also work until the burr is either removed, or diminished in size. At this point, I move to the next stage.
The 4000-grit Japanese water stone is used next, and they are best when used with water, as that allows the metal it removes to float off of the stone, rather than imbedding, even though it still builds up over time. If you worked the previous hone until you couldn’t feel a burr on either side of the blade, you just work with this stone until you see the change in the scratches on the cutting edge. It should change to a dull grey, with no real obvious scratch marks. When consistent on both sides of the blade, you’re ready to move on.
Next up is the 8000-grit Japanese water stone, and the procedure is exactly the same as the last, but I use a little less pressure as these stones can be more delicate than the 4000-grit. You still need to use water as it’s lubricant, and this time you’ll look for a nicely polished cutting edge. When both sides are complete its on to the last stage.
I use a honing paste that came with my Tormek T-7 sharpening system, and was included to apply on a leather covered wheel, for final honing. I’ve found I like to use this compound on a small piece of wood, that is similar in size to the Dia-Fold’s honing section. It is comfortable to hold and present to the blade, in a similar fashion. Apply the compound either directly to the wood, or put a small dab on your finger, and smear it onto the wood so there is a very thin layer in the area you plan to contact the blade. If it is too viscous, you can spray the work area of the wood with a very small amount of WD-40, which will allow it to spread easier.
After working both sides of the blade, and seeing they have a highly polished cutting edge, you are working sharp. I take a paper towel, or another sort of rag, and extremely carefully remove any excess compound that has transferred to the blade. The low area in the hollow grind is especially noticeable for catching the compound. When you do this the first time, make sure you start towards the thicker part of the blade, and move out past the cutting edge. Do not move back towards the blade in the same manner or you will likely cut yourself. Just raise up away from the blade and circle back down to hit another area. After you’ve gotten more comfortable, you might do as I will, and “pinch” the blade while removing the compound remnants. If you do not feel totally confidant in this, just stick to the original method, as it is not important to go any faster.
After using the knife to carve wood, you will likely come to a point where it doesn’t seem to cut quite as well. As long as you haven’t hit any nails, or staples in the wood, you can probably get away with just re-doing the Tormek compound process, to refreshen the blade. If this doesn’t seem to do the job, you can go back as far as you deem necessary, potentially all the way to the Dia-Fold. If you touch-up the blade regularly, rather than waiting until it is quite obvious the cut is not as good, you may find the Tormek compound is all you need to use to retain a very sharp knife for a long time.
As time passes, and the knife honed over and over, the hollow grind shape will slowly disappear. This will likely require you to change your process slightly, as the reference “feel” of the hollow grind will no longer be there to guide you. At this point I apply black sharpie to the bevel of the knife, and pay close attention while I work, to see when I am removing the black from the full bevel. I lock my wrist at that angle, and work until I have a consistent scratch pattern again. All of the other steps are the same, except you may need to use the sharpie for each stage of honing.
I hope this, along with the included videos below help all the owners of my knives to continue carving for years to come. Please don’t hesitate to let me know if you have any questions or comments.
For those that follow me on my other social media, I mentioned I’d write an article describing how I am burnishing the edges of my leather projects, as it is relatively simple and doesn’t require much “elbow grease”! So let’s get after it and I hope this may make it easier for anyone that is trying.
I’ve been making some leather sheaths for knives and some other items for a few months now, and have a basic background with working leather as a young kid, but it was focused more towards putting together pre-created pieces together or carving basic enhancements. My current projects are getting better in all aspects, as I’m fine tuning little by little. The edges on all of my recent items were left “raw”, as in the same surface texture as the cutting device transferred. I’ve looked at a number of professional leather pieces and almost all have edges that are what I’d best describe as “finished”.
I don’t recall ever see anyone finish the edges like that when I was young, at least not on the things we were making, but I really do appreciate this look. With that in mind, I decided to try a number of things in the attempt to create a similar look on my edges. I started off with some sand paper, and depending on how consistent the flow of the lines were, started at 100-grit or 150-grit, followed by some 220-grit. I read where some were using different types of waxes, during the burnishing stage, and others used oils. I decided to go with a blend, by using Jojoba oil, which is a waxy oil. After applying a coating to the edge, I tried a number of different smooth/hard items, but nothing really seemed to occur.
I decided to apply a light coat of Liberon Black Bison wax to the edges, and left it to dry. This time I tried using my Dremel with one of the felt wheels, to see if I could cause some friction action, and get the look I was after. This still left it a long way from my target look.
Next I put a 12″ length of hard maple onto my Teknatool Nova XP wood lathe, and using a gouge, created a groove a little bit wider than the widest width on my current pieces. The gouge left a very smooth surface in the groove, and I applied some wax all the way around the shaft, so the groove was ready to do the work for me. (or at least I hoped so)
I turned on my lathe and brought the speed up to 1800 rpm, moved the rest out of the way, and then brought the edge of my sheath under the groove. I raised the sheath enough so it was touching the rotating groove, and started working the sheath slowly along so that all of the edge received the results of the spinning groove.
The results were nothing short of surprising! The mix of wax, oil and the friction provided by the spinning piece of maple, provided a nice sealed surface to the edge and raised the overall level of the sheath.
I brought two other recent sheaths out to test to see if this was a fluke, or if I could repeat it at will. I decided to again apply the Jojoba Oil, followed by Black Bison wax, and the maple shaft did the rest. Both of the test sheaths looked equally as nice as did the first sheath.
I will keep this maple shaft for any future leather projects, and mount it on the lathe whenever it is needed, so it won’t take up any real space in the shop in between uses.
I hope you enjoyed this article and it helps you improve your projects. As always, please make sure to let me know if you have any questions or comments.
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