How to Reprofile the Edge on a Dull Knife
Use a knife often and hard enough, and you'll have to reprofile the edge. Here's how it's done
Use a knife like you ought to use a knife—that is, often and hard, and sharpened frequently—and you’ll need to reprofile the edge as you hone away more and more steel. Michigan sharpening expert Jason Bosman of Traditional Sharpening (known as “MrEdgy” on YouTube) reprofiles even out-of-the-box blades. “Reprofiling your own edge makes it a product of your muscle memory and personal technique,” Bosman says. “You can put it back time and again because it’s yours and no one else’s.” You’ll need a coarse 100- to 220-grit stone. For blades of hard powder steel, use a diamond stone of similar coarseness.
Hold the blade at a 90-degree angle to the stone, and pull the edge across the stone as if you’re cutting it in half, as if it were a loaf of bread. Grind away the damaged steel at the edge until all imperfections are gone and you have a flat, dull edge.
Use an angle guide to set the edge angle. Bosman prefers an acute 15 degrees per side. Pass the blade across the stone with a back-and-forth scrubbing motion without lifting the blade. “Let the stone do the work,” Bosman says. Make 10 scrubbing motions on one side, inspect the edge to make sure the grind is even from heel to tip, then repeat on the other side. Inspect after each set of grinding passes by shining a bright light on the edge and rotating the blade from right to left. Look for a burr that will show up as a shiny glint. When you can flip the burr from side to side with a few light passes on the stone, you’ve set the edge angle and are ready to reduce the burr.
To prepare the edge for final sharpening, use increasingly softer single strokes (no scrubbing) as you gradually step down the number of passes per side from five to three to two to one. Inspect the edge after each set, making sure the burr is getting smaller and you are maintaining a consistent angle. Once you can flip the burr from side to side with a single light pass, you can move to finer stones to refine the edge to your liking.