Different carvers use different ways to sharpen their carving knives, nearly because, there is no right method of sharpening your wood carving tools. After sharpening, you want an outcome that can shave a thin slice off end grain as easily as possible. There are two ways you can use to sharpen your knives, sharpening by hand or by machine. Sharpening by hand can be done as quickly as by machine and give results just as good.
Before going to look for sharpening accessories, you should know the three terms that will help you choose the wood sharpening accessories that you need. These are; bevel, burr, and polishing.
What Features Should A Right Bevel Have
Bevel is very important when it comes to sharpening wood carving tools because it will determine whether you will carve or not. The bevel is the primary part of the tooltip that is sharpened to create a sharp cutting-edge and woodcarvers have different tastes when it comes to bevel angles. Generally, what you want to do when sharpening your tools is to increase the angle as you increase the hardness of the wood.
When sharpening to carve woods like pine or basswood use a shallow angle of 15-20 degrees but when carving hardwoods like walnut and oak, use a steeper angle of 20-35 degrees.
The reason you use a steeper angle for hardwoods is for the knife to last longer because it dulls quickly when you use a shallow angle dealing with hardwoods.
It’s possible to use the steep angle on softwood too but you have a hard time pushing the tool through the wood. If you decide to use a mallet and a chisel, the steeper bevel is the best option.
A flat bevel is the most desirable compared to other bevels like a rounded bevel which makes the tool roll out the cut prematurely, a hollow ground bevel makes the cutting edge fragile and subject to quick dulling.
Ways To Shape A Bevel
There are two main ways to shape a bevel one of them is the use of sandpaper and the second is the use of coarse sharpening stones.
Shaping The Bevel With Sandpaper
Sandpaper is the best option to shape a bevel because it is available in different coarse grits. The best sandpaper I would recommend when shaping your bevel is the silicon carbide sandpaper and it is mostly known as wet-and-dry sandpaper. This sandpaper shortens the amount of time you’ll take to shape your bevel. Carvers prefer this and keeping the sandpaper wet will aid the sharpening process.
The best way to use the silicon carbide sandpaper is to back it up with a flat surface to give you the best outcome after sharpening your tool. Make sure the sandpaper stays wet all through your tool sharpening.
Shaping The Bevel with Stone
Sharpening with a stone works the same way. The grit in the stone wears out the metal blade as it passes over the surface. Doesn’t matter the type of stones you use be it diamond stones, oil stones, or water stones. The best way to sharpen using this method is to use a coarse stone until the bevel is shaped and work your way through the finer grits.
When using oil stone, it is recommended by the manufacturers to apply a little oil before sharpening. The reason for this is to float the metal particles away. There are sharpening oils available for buying but you can alternatively use kerosene, mineral oil, or lightweight motor oil.
Course water stones are usually soaked in water before sharpening but the ones with finer grits just require a spray of water. Ceramic stones and diamond stones do not require any lubrication, a regular cleaning with soap and water will do the job.
The good thing about sharpening stones is that you do not need to worry about replacing them, but with sand, you will be forced to replace them after it is worn.
What Process Should I Follow To Have A Constant Bevel?
When sharpening a bevel, it is important to keep your angle constant to prevent getting a double bevel.
Position the sandpaper or the sharpening stone depending on what you are using to sharpen, so that its length is perpendicular to the front of your body. This way, you can eyeball the angle of the tool to sandpaper or stone, and this will help you to maintain a constant angle through the sharpening process.
When sharpening Tools with short bevels like gouges and chisels, place a visible guide at the end of the glass to help you keep the angle constant. Use a side-to-side motion with the gouges and the V-tools. If you decided to sharpen with the direction of the bevel, even the finest grit will create a slightly scalloped edge which will give you a craggy cut.
If you have trouble seeing the progress, coat the edge with a black magic marker.
The best way to maintain the same level is to pace the top of the bevel down first and slowly rotate it until the edge rests on the stone. Continue sharpening your carving tool until you have a burr the entire length of the blade.
When sharpening your carving tools, ensure to keep the elbow of the handle-gripping body and this reduces the tendency for the cutting edge to move up and down.
We sharpen our tools until we achieve a burr also known as a wire edge. As you continue sharpening, the metal on the end of the cutting edge becomes very thin and usually rolls over. This tells you that you are close to having a sharp edge. Always sharpen your tools till the wire edge is across the lade uniformly and for the best result, maintain a consistent angle when sharpening.
Despite the need to create a burr, it has to be removed because if it is not, the tool might not cut at all. Working through finer grits of sandpaper should take it off.
Fine sharpening stones, for example, hard black Arkansas stone will also remove the wire edge. This also requires maintaining a constant sharpening angle. To make sure that the burr is gone completely, stropping is the method you use and it removes the burr and polishes the edge. A polished edge will glide through wood and you will enjoy using it for carving.
Stropping is the method used to polish your edge by removing the burr that is left after carving.
All you need to achieve this is a strop and abrasive or stropping compound like hard leather. A carver’s strop consists of hard leather glued to a piece of wood. The two popular stropping compounds are aluminum oxide and chromium oxide which can come in powder, paste, or stick form. Remember when stropping using chromium oxide, use small amounts because it is toxic when used in high concentrations.
To start stropping, apply a small amount of abrasive compound and when stropping gouges, chisels, and V-tools, hold the tool at a constant angle and apply pressure pulling the tool across the leather. When sharpening gouges, bend a piece of leather and push out of the channel to avoid cutting the material. The traditional way to remove the burr from inside a gouge is to use a slip stone, especially one’s designs for de-burring an inside edge.
The bevel is held at a constant angle and the tool is pulled across the leather away from the cutting edge.
When stropping a knife, lay the blade flat on the leather and pull it with cutting-edge training. If you push any of the tools or strop them from side to side, you are liable to cut leather. You don’t need much accuracy when it comes to stropping but the strokes should be long and firm.
If you come across “tracks” on the stropping compound, the tool probably has a burr so, continue stropping until it disappears. If you are unable to remove the burr, return to the finer-grit sandpaper.
How Do You Choose The Best Stone
I’ll share with you two tips to look at when buying sharpening stones
Try to choose a stone that does not require oil as a lubricant. The reason for this is a stone that uses oil for lubrication is difficult to clean and it can also put an unwanted stain on your project not to mention the mess on your hands and clothes. Most stones will work well with water and I suggest you choose to buy that.
When buying sharpening stones, it is good to buy both medium and fine stones to cover a range of sharpening needs.
Conclusion on Sharpening carving tools
If you want to have a good experience when carving you need sharp tools and what have shared with you above will help you know how to sharpen your tools when they go blind.