Many sports enthusiasts believe that sharpening a fillet knife to a lasting razor-sharp edge is a skill few can master.
But it’s not that hard, and much less expensive than buying new or having someone else do your sharpening. It does require practice – just like most things you want to become good at.
Knife sharpening basics
Any cutting tool has a sharp side with at least one angled edge. As you use the tool, the edge is shaped at a microscopic level – and that edge degrades with use until the instrument no longer functions properly.
If, like a butcher or sushi chef, you routinely maintain your edge, frequent, light honing (straightening or deburring) may be all that’s needed to bring the blade back to its original form for a good while.
Hunters, anglers, woodworkers, and others often use a tool until its edge has lost its original symmetry. And, eventually, any edge will need a more aggressive sharpening. That’s when it’s time to re-establish the angle.
Natural stone and leather are traditional methods of grinding and polishing an edge. But these techniques have shortcomings – they don’t maintain a perfectly flat edge for long. Whetstones can be imperfect to begin with and as they become concave (dish shaped) over time the uneven surface distorts the edge of your blade. In the recent past, natural stone and leather was used to grind and polish an edge.
V-shaped, carbide pull-through sharpeners are also available, but they can tear the steel and may not match your edge. Electric wheel sharpeners can hide wear on the stone and may not match the angle of your knife, and belt sharpeners can cause the surface to flex and become concave due to pressure on the belt.
Whatever method you use, you must exactly match the angle of the original edge to end up with a terrific edge.
It’s all about the edge
To maintain a perfect edge, ensure you:
- Have a perfectly flat surface;
- Match the exact angle of the original grind; and
- Sharpen both sides of a knife-edge with equal pressure, stroke length, and repetition.
Many sharpening systems come with a guide to position the knife-edge at the correct angle. This is helpful if it sets the guide precisely to the correct edge. But, sharpening your fillet knife and then your hunting knife without changing the angle will likely ruin one or both blades. The hunting knife will be more obtuse, while the fillet knife will have a more acute angle.
Not all hunting knives are exactly the same, either. Even the same brand can have a slightly different edge angle as many knives are still handmade by skilled individuals and not precise machines.
For example, hunting knives and butcher knives can range from 18 to 26 degrees, fillet knives from 12 to 18 degrees, and replaceable blade knives (yes, you can sharpen these, too) from 7 to 12 degrees.
Test your sharpening skills
So how do you know if you’re sharpening your particular knife at the right angle? The easiest way is to colour the cutting edge (secondary grind) with a black marker before using your sharpener.
If you only remove the marker off the very tip of the edge, your angle is too obtuse. If only the marker off the shoulder is affected or you’re touching the primary grind, your angle is too acute. Make adjustments as needed.
As you perfect your stroke, you’ll quickly learn that a bench stone is ideally suited to find an edge and maintain it with each stroke. This is where practice is important. Find a few old kitchen knives and perfect your technique on them, instead of your new fillet knife.
A bench stone is the solution to the first of the three sharpening rules: start with a perfectly flat surface. I recommend the DMT Diamond Bench Stone. It’s guaranteed flat and uses high-quality micronized monocrystalline diamonds. Diamonds are harder than any steel you will be cutting (even the titanium-bonded 4116 German stainless steel used in high-quality Cuda Brand knives) so they won’t dish like a natural stone surface.
Quality diamonds cost more, but last much longer. This actually makes the DMT sharpener cheaper in the long term, because you don’t need to replace it as often and it’s far easier to maintain. DMT offers a variety of styles and sizes to suit your needs. Whether you’re a butcher, hunter, angler, woodworker, or gardener, all your sharpening needs are covered. I trust it with my most expensive knives.
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John Ward is vice president and general manager of Orangeville-based Acme United Ltd.