When to Sharpen Chisels and Planes: Clear Signs Your Tools Are Dull

A sharp chisel, struck lightly with a mallet, sinks into the wood with a “Zut” sound, advancing smoothly with reliable feedback. It feels as if the wood is accepting the blade.

But as the edge dulls, the blade stops at the “entry point.” The same force no longer makes the chisel bite, and instead it slides across the surface. You end up needing extra force to make progress. With hardwoods, the difference is especially clear—the blade no longer goes in naturally.

A keen edge cuts fibres cleanly, leaving a shiny, smooth surface.

When the edge grows dull, instead of cutting, it presses and crushes the fibres. The result is a whitish surface with crushed and fuzzy traces. This difference is especially visible in softwoods.

Striking hardwood can cause small chips in the edge. Even if they are invisible to the naked eye, you can feel roughness with your fingertip, and fine lines will appear on the finished surface. If you keep working like this, the chipped sections create resistance, fibres catch, and force escapes unpredictably.

Such chipping directly affects your work: lines in the finish, or a chisel that no longer enters smoothly. When you notice these changes, it’s a sign you need to resharpen.

This is most noticeable when paring end grain by hand. While sharp, the chisel makes a steady “Zut, Zut” sound, cutting fibres with pleasant resistance. Sound and feel are in sync, moving in a consistent rhythm.

As sharpness fades, the sound changes. In earlywood, “Zut” becomes a duller “Guh,” showing that fibres are being crushed. In latewood, the sound breaks into a “Gak” as the blade stops abruptly.

When the rhythm breaks or the sound turns heavy and muffled, that is a clear sign that sharpening is due.

With chisels, when the blade no longer enters cleanly, surfaces look cloudy, or the rhythm of sound is lost, these subtle changes all signal dullness. Don’t ignore them—resharpening at this stage leads to far more accurate woodworking.

When sharp, a plane produces thin shavings with the blade set just barely proud of the sole.

As the edge dulls, this setting no longer engages the wood, and you must extend the blade further. At that point, only thick shavings come out, and the smoothness of the finish declines.

If you find yourself thinking, “This setting used to cut fine, but now I have to push the blade out more,” that’s a sign it’s time to sharpen.

In other words, when your shavings change from transparent and floating to heavy, ribbon-like strips, the blade is asking to be resharpened.

When sharp, a plane makes a crisp “Shhh” sound—clear, light, and steady in pitch.

As the edge dulls, faint distortion creeps into the sound. When planing long boards, the once-consistent pitch begins to waver slightly, with subtle rises and falls that weren’t there before.

At first this may be hard to notice, but with practice you’ll clearly hear the difference. That small change in sound is the blade telling you, “Sharpen me.”