Sharpening Handbook

Stone Carving Point Tool

Edge Angle

Guidelines shown below are for the cutting edge angle.

Point tools generally use a sharper angle, in the lower end of the range. Also, point tools are typically ground with an overall convex grind.

Frequent sharpening is recommended to maintain the tool's shape, and is needed for safe performance of the tool.

The marble not yet carved can hold the form of every thought the greatest artist has.

Michelangelo

General Guidelines

Material

Sharp
ness

Comments

Softer stone
(e.g., chalk, soapstone, & pumice)

25° - 35°

General stone
(e.g., limestone & marble)

30° - 40°

Harder Stone
(e.g., granite & basalt)

40° - 60°

Carbide inserts are usually embedded in the tips of these tools.

Notes & Comments

Information regarding Grindstones

Use larger angles for roughing out, and sharper (more acute) angles for finishing cuts.

Special Notes for Tools with Carbide Inserts: Do not cool by dipping in water : this will generate shocks in the metal, and cause the carbide to crack.

When sharpening, one of the following options is recommended.

Leave corners slightly beveled, or
Edge up on the final grind.
- Leave the final 1.5 mm (1/16 inch) unground. This is because the rough grinding of the carbide introduces cracks and makes the edge more brittle. By stopping short of the edge, this is minimized.
- Then, use a high grit wheel should be used to make the edge smooth with minimal cracks.
- A very high grit grindstone should be used if a very smooth carving surface is needed, or if the material is very soft.

Special thanks to Oleg Lobykin at StoneSculpt - Custom Stone Carving for providing the guidance.

Sharpness Scale

Example icon

Sharpness scales (as shown in the grey icon to the left) are used to indicate the recommended sharpness for the blades noted above. You can click on any of the icons showing the sharpness scale and be redirected to the page describing this more. Lower numbers are duller; higher numbers sharper.

These are general recommendations; you will need to use your own judgment, based on the knive’s intended purpose.