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.
Ok, sorry again for the lack of recent posts, but my last post hopefully informed everyone as to why I’ve been away from the site.
I bought some more material for knife blades, even though it wasn’t quite as thick, and had a different “feature”. The blanks I bought had some holes in them, and the location of the holes presented an issue, where I would need to either make the tang much more narrow or include a section of a hole. I decided on the latter, which had some positive aspect (stronger), and not quite negative, but I suppose challenging (tang shape other than rectangular adds some extra work) aspect to it.
As I do regularly now, I placed the tang of a blade on the inside of one half of the handle, and trace around the tang with a pencil. As this batch of knives is a little bit smaller than the most recent knife I wrote about (here, in case you haven’t yet read about it), the tang isn’t as wide. Both the width of the tang, as well as the shape (with the small portion of a circle), changed my work strategy a bit. On the last knife, the tang was wide enough to comfortably use the standard iron in my Lie-Nielsen No. 71 (Large Router Plane) to excavate the waste wood, and providing a flat and level “floor” which the tang rests upon.
The smaller tang on the current knives is too narrow to effectively use the No. 71, unless I was to shift to one of the small blades made for the Lie-Nielsen No. 271 (Small Router Plane), but I currently only have the 3/32″ Pointed Tip blade which wouldn’t really be very efficient. They do offer a 1/4″ Square Tip blade, and with the area nearest the hole/circle pinching in to even more narrow width, it would still fit nicely.
I don’t presently have a 1/4″ Square Tip blade, for my No. 71, so it was time to improvise. I recall seeing an old home-made tool, that used a small block of wood for its body, and a narrow chisel as the blade, to create a router plane. I quickly went through my off-cuts and found a small piece of white oak (this could have been a section of 2 x 4, or other softwood, as well), and an old Stanley chisel. I made sure the chosen chisel would fit into the tang recess areas, and then compared the chisel’s dimensions with my drill bits, and made sure the bit was just slightly smaller than the chisel. On a regular router plane, the blade is made from an “L” shaped piece of steel, and the cutting portion of the blade is held so there is a clearance angle between the heal of the blade and the work surface. Knowing this, I held the chisel I planned to use as my router plane’s blade, and when I saw a similar clearance, I set my adjustable angle gauge so it mimicked the angle of the chisel’s shaft. I held the angle gauge up against the side of the oak body, making sure to pay attention to where the blade would come through, which I wanted to have just behind the leading edge of the body. After determining where the blade would exit, I again used the angle gauge to locate the entry point for the blade, and the drill bit. Before I started drilling, I placed the angle gauge off to the side of the entry point, so I could use it as a visual guide to make sure I drilled the hole at the correct angle, similar to what Peter Galbert does when drilling into his Windsor seat blanks.
With the hole drilled (which is the basic path the chisel will follow), I used the same chisel planned as the blade, to remove some of the excess wood, but also used some narrow Japanese chisels to speed up the process. I worked mostly from the top side of the body, but as it got closer to coming through the bottom of the body, I sighted in a few well placed strikes with my most narrow Japanese chisel, to create an opening much closer to the size of the chisel. This helped prevent the wood breaking out, when the main chisel first came through the sole, and the location of the smaller chisel cuts made sure I didn’t create a loose fit. The chisel/blade will only advance with a firm strike, which gives me confidence the “blade” won’t shift either in or out, during use.
After I had the blade all the way through, I traced out an area surrounding the blade, which I removed so it wouldn’t jam up as quickly.
Using the new tool
After I chiseled away bulk wood in the tang-waste area of the knife handle, I used this new tool to make sure all of the tang area was the same depth. When I shifted to the second half of the knife handle, I decided to see if I could get the tool to behave decently, with it already set to full depth. I simply rotated the whole tool up on it’s leading edge, which raised the cutter away from the wood. I slowly pivoted the tool down until it was lightly cutting, and went over the whole tang area. I pivoted the tool’s sole down closer to the work, removing material until even again, and repeated until I was at final depth. This made for a fairly rapid process, without the need to stop and change the projection of the blade.
While this purpose-made tool worked decently, I still prefer the blade presentation the adjustable metal router planes provide, as I noticed more chattering on my new tool. One thing I did, after I was finishing up, was to take another similarly small chisel and use it as a scraper. I held it almost vertical, then tilt it slightly towards myself (around 15 degrees), making sure the flat back of the chisel was facing me, and pull this “scraper” towards me, to take super-controlled “cuts”. You really don’t need to create a hook on a chisel’s cutting edge that you put into use as a scraper, and I think you’ll find it amazing just how much control you have, and how fine the resulting surface is. One must, and this is for both the router plane build as well as when using it for scraping: make sure your chisel is sharp! It truly makes all the difference.
Thank you for stopping by to check out the article, and I hope you will find the information useful. As always, please let me know if you have any questions or comments.
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