Tips for Knowing Knives

How to Know if Your Knife Is Sharp Enough

Here are some easy ways to tell if you knife blade is sharp enough to carve wood.

• Under a strong light source, hold your knife blade vertical, sharp edge up. If the light reflects off the edge of the blade, it is dull. If no light reflects off the edge, that is good.
• Take a styrofoam coffee cup and try to carve the foam. Turn the cup into the knife edge as though you are trying to carve a Slinky. If the knife tears the foam and bunches up against the blade, or if you can hear the foam tearing, then the knife edge is dull. If the knife cuts the foam smoothly and quietly, then it is good.
• Try to carve a piece of wood across the grain (growth lines). If it is hard to cut and and the knife tears the wood, then the blade is dull. A smooth, easy cut is good.
• Cutting paper or cardboard is another way to test but the wood fiber in those materials, especially the latter will dull the edge quickly, so be careful when using that method.

Remember, the best knife blade for wood carving is a short straight edge, no longer than 1.5" long The straight edge allows for easy sharpening of the whole blade. The sharp tip is necessary to carve detail with V-cuts and Stop cuts.

Sharpening Instructions

Years ago, I purchased a sharpening stone set from a company called Smith's that included some great guidelines for sharpening knives. With apologies, here's a copy of that long-ago instruction sheet.

How to Thin the Blade of your Carving Knife

PROBLEM: as you sharpen your carving knife more and more, do you wonder why the knife does not seem to hold the edge for very long, even when you use the same technique to sharpen it?

EXPLANATION: If you only sharpen the edge of the blade, then it will start to look like figure A (see image, right). You do not have to cut your blade in half to realize that it should look like figure B. The thinner the blade, the easier it cuts through wood.

SOLUTION: Thin the sides of the blade by laying it flat on a coarse stone or belt sander, then wear away the excess steel on both sides of the blade (figure C) as shown. Press hard because you are wearing away more steel than when sharpening the edge.