By how the saw behaves rather than how the teeth look: a blunt blade needs more feed pressure, burns the cut, produces dust instead of chips, and leaves a rougher edge than it used to.
Carbide teeth do not visibly round over until they are far past their best, so the symptoms come first.
More pressure. The clearest sign. A sharp blade is drawn into the cut; a blunt one has to be pushed.
Burning where there was none. Especially in the same timber you cut last month without trouble.
Dust rather than chips. A cutting edge produces chips. A rubbing edge produces powder.
A rougher finish, particularly a fuzzy edge on the underside.
Before condemning it, clean it. Pitch and resin build up on the carbide and behave exactly like bluntness. A soak in a resin solvent and a brass brush restores a surprising number of blades people were about to replace.
Sharpening. Carbide-tipped blades can be reground by a saw doctor, usually several times, for a fraction of the price of a new one. It is worth it on a good blade and not on a bargain one.
Last reviewed 2026-08-12