17 April 2009

EDC Knives: Blades

This post will not discuss blade steels, but rather blade patterns, geometry and edges. A blade pattern is the general design of the blade, which is oriented to its intended usage and function. But for every pattern there are distinct variations of geometry and edge that further affect its functionality in performing various tasks.

I’ll just refer you to this wiki article for an overview of the various blade patterns, to which yet others could be added (consult Stewart’s Guide for a fuller survey). Multi-blade slipjoint folders will usually have blades of multiple patterns, suitable to the knife's intended usage. For example, the 3-blade “whittler” I have in pocket today has two clip blades, one long and one short, and a pen blade (a small drop point). This makes these slipjoints very versatile.

Tactical knives have just a single blade that has to do everything, so blade pattern is a very important consideration. The most popular blade patterns are probably drop point and tanto, in countless variations. The drop point is a superb general utility shape. It is made for slicing rather than thrusting, but it can also be ground into an effective point for good penetration.

The modern American tanto blade is a dedicated thrusting design. Cold Steel demonstrates their tantos punching through car hoods and 55-gallon drums. I don’t need to do a lot of that myself, so tantos do not appeal to me so much. Especially since they are lousy for general cutting. I personally think their popularity is driven by their “wicked” appearance, which also contributes to the general weaponization of knives in public perception, a thoroughly bad thing. Not to say I'll never own one, but they make little sense for EDC.

For good slicing ability, you want to look for a knife with a broad cutting surface and good edge “belly,” the curve just behind the tip of the blade. For this reason, tanto, wharncliff (straight-edged) and hooked blades are of poor general utility. Drop, clip and spear points with simple or recurved bellies are simply better cutters in general use.

Also beware of knives with deep hollow grinds and narrow cutting planes ending at the middle of the blade. Hollow grinds give a very thin and sharp edge, but that thin edge may chip easily, especially with cheap steels. I prefer a full flat grind, a straight taper from spine to edge, which is more expensive to machine but yields a very sharp, strong edge with a broad cutting plane. Think chef’s knife.

(top) Spyderco Atlantic Salt rescue knife, a hollow ground wharncliff with full SpyderEdge serrations; (bottom) Spyderco Tenacious, a flat-ground drop point with plain edge; (right) CRKT M16-14SFG, a combo-edged tanto blade with excellent Veff serrations

Edges come in three basic types: plain, serrated and combo (half-serrated). For general use and ease of sharpening, I find a plain edge is best. However, for quickly severing ropes, or seat belts, or anything that may be sawed (serrations are just little sawteeth), good serrations are incredibly effective. A combo edge aims for the best of both words, with just the back half (more or less) of the blade being serrated. On longer blades, at least, this is often fine for general use, though it is still a compromise. But there is no best blade or edge. It all comes down to intended use and preference.

Next up: Cheap Chinese clones

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