Using Northwest Coast Style Bent Knives
Over the last few years, a large number of woodcarvers have discovered the pleasures and convenience of carving with bent knives. I am particularly fortunate to live on the west coast of Canada where a vibrant Indigenous Art community has developed a number of versatile blade designs. These beautiful and highly functional blades enable carvers to undertake a vast range of complex concave and convex carving with far fewer tools than would be required using European-style gouges and chisels. Having been exposed to bent knives several years ago, I now find them an indispensable and favoured part of my tool kit. Although they may not be as readily available to British carvers as they are here, a number of exceptional Canadian and US craftsmen are now making them for the commercial market and they can be mail ordered with little difficulty.
What is a bent knife?
Bent knives differ from European-style hook knives in that they are seldom ‘fair’ curved. Most often they begin flat near the handle and increase curve as they near the tip. This varied radius allows the user to carve a variety of curves by simply altering the angle of blade attack and by subtly adjusting which region of the blade makes contact with the wood. The blades themselves can range from wire thin, short blades to hefty, wide blades of several inches length. Blade radiuses range from nearly flat to almost circular and the hooks can vary from sharp to shallow, from just the tip to the entire blade. The bent knife is generally sharpened on both sides of the blade, a feature that allows multi-directional cutting. The bevel may occur on the outside or inside of the curve depending on the type of carving to be undertaken. Inside bevels are generally more aggressive and outside bevels allow the knife to cut tighter radiuses.
How are they held?
Whether shallow or deep, the principal purpose of a bent knife is to facilitate smooth cutting of curves. They are exceptionally aggressive, but are easily controlled and can be used for both rough cutting and delicate finishing. Although the cutting is primarily done on the pull stroke for maximum control, the knives cut equally well on the push stroke. They are most often held in a fist grip with the thumb protruding along the handle where it assists the wrist in levering the knife along the cut.
How are they used?
Thanks to the double-sided blade, the knife can be drawn or pushed. Well sharpened, it can be drawn along the grain or across it. A bent blade is remarkably versatile, but can be aggressive. Beginners should take care not to try and cut with them as they would with straight knives. Bent knives are greyhounds and will
take off like rockets if allowed. Inevitably this manifests itself in deep cutting that jams almost immediately and causes terrible frustration. To properly cut with a bent blade, lay the back of the blade flat on the face of the work piece and gently begin drawing the knife toward yourself. Even without an angle being applied, the tool will very likely begin grabbing at the wood and will start cutting. As with gouges, the bottom of a curved cut can create some problems for bent knives. This area where the grain changes direction can easily be torn away or can cause the blade to jam. The bent knife can be used to overcome this by cutting from both directions and even across the grain. Just be certain to keep the cuts very shallow.
How do I sharpen them?
Well-sharpened bent knives, which aren’t being abused, maintain their edges for a long time. Frequent honing will enable you to retain the razor-sharp edge that makes these knives the wonders they are. Sharpening is simpler than it might seem but it must be undertaken carefully and conscientiously to ensure the correct angles are maintained and maximum sharpness achieved.
What could possibly go wrong?
Aside from the usual problems that accompany all knives such as getting slashed by them and cutting off too much material with them, the main problem for bent knives is damage to the blades. If the edges come in contact with other metals or hard objects, they are easily nicked. A major problem, especially for aggressive beginners, is a tendency to snap the blade tips off. This happens when they are used to pry a cut, when they are dropped or bumped or when they are yanked out of a stuck cut.
Where do I get them?
Once upon a time, because they are handmade, bent knives were difficult to source unless you were ‘in-the-know’. In the last several years, however, a number of metal craftsmen have stepped up to offer a range of fabulous blades at extremely competitive prices. A quick Internet search will reveal several excellent makers all of whom are dedicated to making excellent tools. Many knives come complete with handles, but several makers will sell blades that you can finish at home with handles made to your personal specifications and hand size. Making your own handle is fairly simple and straightforward and is an excellent way to use up that beautiful scrap of wood that you’ve been storing under the bench for the last 10 years! A bent knife or two makes an excellent addition to a woodcarver’s arsenal and even the most die-hard chisel and gouge aficionado will appreciate the versatility of these unique tools.