In addition to gouges, knives, and wood, you must understand and be able to apply basic principles of sharpening. An overview of the following topics will be covered:
- Sharpening Stones
- Sharpening Stone Lubricant
- Sharpening Angle
- Feather Edge
- Power Sharpening
Two sharpening stones are required for sharpening. Use a 200 grit stone to shape the cutting edge of either the gouge or the knife. Use 400 to 1,000 grit stone to create the cutting edge on the instrument.
Sharpening Stone Lubricant
Sharpening stones come in two flavors – oil stone and water stone. Mineral oil is a good lubricant for an oil stone. The lubricant floats away the metal particles during the sharpening process. Adequate lubricant performs two functions. First, the sharpening stone will maintain its original shape. Second, adequate lubrication keeps the stone clean.
An angle of about 15 degrees is best for knifes and 20 degrees for gouges for soft woods. Harder woods require about a 25-degree angle to hold a cutting edge. Maintaining a consistent sharpening angle during the sharpening process is absolutely essential.
To create the cutting edge required for carving, it is essential to have a razor sharp cutting edge. This is accomplished by pulling the edge into the stone as if trying to remove fuss from a peach. That is, move the cutting edge into the stone. Make two strokes on one side. Turn the blade over and make two strokes on the opposite side. That is, alternate sides of the tool so as to work both sides equally. Keep equal pressure along the entire length of the blade.
Honing is the final sharpening process. Leather is the preferred material for honing. A fine abrasive must be added to the leather surface. Honing polishes the cutting edge to a mirror finish and removes any burr. Move the edge away from the leather strop to prevent cutting the leather strop. Three or four strokes on each side are adequate. Additional strokes tend to round the cutting edge.
Several power-sharpening machines are on the market. All of the above thoughts apply to power sharpening. A word of caution is offered. Much care must be taken to not over heat either the carving knife or the gouge. If the tool feels hot to the touch, it is too late. Heat can remove hardness and make junk out of a fine cutting tool very quickly.
It is absolutely essential to maintain a razor edge on your carving tools. Sharp is safe. Dull is dangerous. After the cutting edge is shaped with the 200 grit stone, the cutting edge is formed using the 400 to 1,000 stone. The cutting edge is maintained with the leather strop until the cutting edge is rounded and shaping is again needed. Please note the frequency, which each tool is used to create and to maintain the cutting edge. Also, pay careful attention when using a power tool to sharpen your carving tools. Most beginning wood carving books include sharpening information.