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Sharpening Edges: The Foundation That Makes Every Cut Better

I will be the first to admit that I have spent most of my tool using life, avoiding and rushing to get through sharpening, and this is because most of us don’t take the time to understand that this is where every project starts. A dull edge is a terrible thing because it makes the tool harder to use, but it also makes it difficult to know if it is actually working properly. A sharp chisel, for example, should be able to slice end grain without any applied pressure at all. A sharp plane iron should leave a planed surface smooth and glassy, as opposed to crushed and torn. So, where do we start? I will get this right out of the way.

A sharp tool is the result of having two surfaces that are sharpened to a high polish meeting at a precise angle. These surfaces are called the “bevel” and the “back”. If either surface isn’t sharp, and one or both is scratched or rounded, the tool will tear instead of slice. When sharpening, it’s always a good idea to start with a coarse stone. For most tools, this could be a 220 or 400 stone. The goal here is to establish or reestablish the bevel angle. For most tools, 25 degrees is a good place to start. This is a good balance between sharpness and longevity. Place the bevel flat on the stone, and raise the handle of the tool just enough so the very edge of the blade is touching the stone.

Then, apply even downward pressure while moving the tool forward in a smooth consistent motion. Keep the angle consistent by locking your wrists and moving your body at the shoulder. This way, your arm and wrist are doing the work instead of your fingers. Do this for 10-15 strokes and inspect the edge in a bright light. You should see a uniform “wire edge”, or thin burr along the edge of the tool. This is a sign that the two surfaces are meeting.

Now, turn the tool over and put the flat back side on the stone. Use light pressure to remove the wire edge. Remember, you only need to polish the back of the blade for about 1/8 of an inch. There’s no need to spend a lot of time lapping the back of the blade. From here, move to a higher grit stone (1000 for example) and repeat the process using lighter pressure and more strokes until the bevel is highly polished and the wire edge is almost nonexistent. Finally, use an even higher grit stone or a leather strop with a small amount of compound to hone the blade to an even higher sharpness.

You will know immediately when you are doing this right. The tool will cut and glide through the wood instead of grabbing at it. One problem you might encounter is when you think you have the tool sharp, but when you go to use it it still tears the wood terribly. This can be due to an inconsistent angle while sharpening, which will result in a rounded or micro-serrated blade instead of a straight one. When this happens, go back to your coarse stone and try to exaggerate the consistency of your angle. If you are sharpening freehand, try using a guide. Once you get the feel for it after a couple of sessions, you can ditch the guide.

One way to test the sharpness of your blade is to hold it flat and use light pressure to pare the end grain of a scrap of wood. If the wood fibers still stand up instead of slicing off clean, go back to the next lower grit stone and try to rebuild the bevel. I would suggest practicing sharpening in 20 minute intervals, 2-3 times a week on the same set of tools. As you get better and better, you will start to enjoy this process and it will eventually become a maintenance thing for you. At that point, you will start to see huge improvements in the quality of your cuts and tools. You will notice that you are getting cleaner shavings, your joints will fit better with less force, and you will be doing much less sanding. Plus, you will have gained the confidence in using your tool to know how it will react in every situation.