When it goes wrong · Sharpen
It cuts well for a day and dulls immediately.
Can you save it?
Reviewed for this symptom
Back to the stone, briefly: raise a small burr again, then remove it with light alternating strokes and a few passes on a strop or the finest stone. The edge underneath is sound; only the finish was missing.
How to confirm the diagnosis
Observable cues, not inferred user state
- The knife was excellent for a day and then blunt
- A wire edge could be felt right after sharpening
- The final strokes were heavy or one-sided
Not this?
- The knife is no sharper after long effort on a stone.
- Chipped edge on a hard blade.
- Honing does nothing.
What actually happened
Only this symptom
The burr was never removed, so the first few cuts tore it off and took the edge with it. Finish with light alternating strokes.
The full mechanism
Shared by every sharpen failure
A knife edge is two ground faces meeting at an apex a fraction of a micron wide. Two different things go wrong with it. In normal use the thin apex rolls to one side; the metal is all still there, just bent, and running the blade along a honing steel pushes it back into line. That is honing, not sharpening, and it is what most people mean when they say they sharpen weekly. Actual sharpening removes metal on an abrasive stone to re-form an apex that has been worn away or chipped, and it is needed far less often. Cutting force rises steeply as the apex widens, which is why a blunt knife is dangerous: it needs more pressure, and it slides off a surface instead of biting into it, with your hand behind all that force.
The full Sharpen lesson — how to tell, where to practise it, what it carries to.
Next time
Prevent this specific failure
Finish every sharpening by removing the burr with light alternating strokes, and hone before each use.
What right looks like
Shared by every sharpen failure
- A sharp knife bites into the skin of a tomato under its own weight; a blunt one skids across it.
- Drawn lightly across a thumbnail, a sharp edge catches and a blunt one slides.
- A burr — a faint wire of metal you can feel on the opposite face — means you have ground far enough on that side and should turn the blade.
- The angle is held constant throughout the stroke; wobbling rounds the apex instead of forming it.