Most important thing for every woodcarver is to have finely sharpened wood carving tools. Properly sharpened wood carving tools guarantees that your wood carving projects will be flawless. There are many ways for sharpening wood carving tools and almost every woodcarver has an unique twist on standard techniques. In one of our previous articles Wood carving tools and Woodturning tools we tried to get to know our readers with basic types of those tools and now we will explain the most common techniques for sharpening them. If you want to learn how to sharpen wood carving tools we advise you to start with one of the common techniques because there are lot of unsecured and untested techniques online with which you will burn and destroy your high quality tools.
There are three steps in sharpening your wood carving tools: sharpening, honing and stropping. In this article we are using the term sharpening to cover those operations that establish the cutting edge of a tool, but that probably leave the edge not actually sharp enough to use. As used in this article, the term honing means to get the established edge sharp enough for actual use, and stropping means to further refine the edge to the point where it is better and smoother. We will try to explain all the three steps and if you carefully follow them your woodcarving tools will be perfectly sharp.
If your carving tools have worn or chipped edges the first thing you need to do is to straighten up the edges. This is not an operation that has to be done too often, but if a chunk gets taken out of an edge then the edge will have to be straightened out before any other sharpening operation is performed. You can use horizontal belt sander with a 150 grit disk for this operation and it will straighten up the edges of your gouges perfectly. When using power sanders for sharpening operations be extra careful. The high speed of the disk generates a lot of heat very quickly, and that amount of heat is enough to take the temper out of the blade. Keep a container of cold water on the table and constantly dip the blade in the water during the operation. The tool should not be in contact with the disk for more than a second before the tool is dipped into the water. If you see the metal start to turn colors it has already gotten too hot.
Now the edge is straightened up and a roughly sharp edge can be established on the tool. Use the horizontal belt sander for this operation as well and with 320 grit aluminum oxide. Keep the water container close in this process as well, and keep dipping the edge in the water every second or so. Carving tools with straight edges, such as chisels and parting tools are sharpened right over the platen, with the edge perpendicular to the direction of the belt. If you are sharpening the curved gouge, position the gouge over the unsupported space between the end of the platen and the front roller. Carving chisels are sharpened on both sides on the belt sander and the gouges and parting tools are sharpened on one side only.
If you don’t have or don’t want to use a belt sander, these sharpening operations can be done by hand on any flat abrasive (stone etc.) of about 320 grit. The process takes much longer but the results are the same.
After you established a roughly sharp edge it is time for honing. With honing process we will make the blade sharp enough to use. This process can be done with sharpening stones or with sandpaper glued to a glass surface.
There are four types of sharpening stones: oil stones, water stones, ceramic stones and diamond stones. Oil stones uses oil as a lubricant to keep the fine metal particles generated by the sharpening process from embedding into the surface of the stone. Waters stones uses water for lubricant, and ceramic and diamond stones don’t require lubricants. Diamond stones are most commonly used to sharpen carbide tools.
Honing the chisels is pretty simple, just drag the edge across the sharpening stone or sandpaper, one side, then the other, until you’ve established a nice sharp edge. For the tools with straight edges the dragging motion is done perpendicular to the edge of the tool. Gouges take a little more work, as the edge must be scrubbed sideways (motion parallel to the cutting edge) over the sandpaper, moving the gouge in a rolling motion. The motion is started with the near side of the gouge down on the far side of the paper and then the gouge is dragged toward you while at the same time rolling it toward you. The motion ends up with the far side of the gouge down on the near side of the stone or sandpaper. Always start with 600 or 800 grit stone or sandpaper and work your way up to the highest grit you have.
Degree of the tool against the stone or sandpaper is something that is opened to debate. Every woodcarver has it’s perfect angle but we advise you to to keep it in the range between 11 and 19 degrees.
At this stage you have to develop a tin edge. This is a small sliver of metal right at the edge of the blade. To check this hold the tool under a bright light. If you turn the blade on its side and look directly down at the blade edge you will must be able to see a shiny line and that the line is the tin edge. A razor sharp edge held under the light is almost invisible, there is no shiny line down the center of the blade! If you can see the edge of the tool, it’s not sharp yet. But the razor sharp edge will be developed in the next stage.
The final stage of sharpening your wood carving tools is the stropping. A good strop must have two sides, one of rough leather and one of smooth hide. On the rough leather side rub in a good layer of strop compound. There are many different strop compounds that can be used and you usually get them when in a set when buying a strop. Lay the blade all the way down onto the surface of the strop, pull away from the cutting edge in nice long strokes! In this stage you will finally lose all the tin edge. Don’t worry, you can never strop too much. For a new tool, about 15 strokes per side is enough. Flip the strop over and work the tool across the smooth leather. Smooth leather gives that wonderful polished look.
At this point you can check if the tin edge is gone by looking directly down at the blade edge. If that edge is has a fine shiny line along it you still have the tin edge. If the blade edge has no shine, you did it, you have a razor sharp tool!