Open a kitchen drawer in anyone’s home, and count how many knives you find that will shave strips from a sheet of paper. It’s a statistical truth that you aren’t likely to find even one, not unless it’s new and has never been used.
There was a time, before the late 1990s, when outdoors knives especially, were intentionally sold dull for reasons of liability (that fact came from the proverbial horses’ mouths at Buck, Ontario, Kabar, etc.), and owners were expected to sharpen blades themselves. If you owned a keen knife, it was because it had been sharpened after it was sold. Sadly, many were never sharpened, and field dressing a deer with them was a ragged, unnecessarily messy chore.
Today’s knives are generally sold with precision-machined edges that are razor-keen – nowadays, there seems to be a competition to see which maker’s blades are sharpest. Even if you never use the knife, corrosion at a microscopic level will likely erode the fine polish that gives a blade its keenness. If you can’t touch-up a lightly worn edge, or flat-out hone an entirely new cutting edge onto a work-dulled blade, then your knife isn’t much more than a poorly designed prybar. A dull knife is a knife only in name.
This article will focus primarily on using hand hones to achieve desired sharpness – which for me, is typically an edge that’ll take the whiskers from my face. The first step to getting there is to understand what constitutes a sharp edge and why it is sharp. If you know what it is that you need to achieve, it’s a lot easier than scraping steel on hone and hoping for the best.
Anatomy of an Edge
Knife lingo-ists usually refer to the configuration of an edge as its geometry. Still, it is more accurate to describe a knife-edge as trigonometry, the meeting of three planes that form a triangle, with the cutting edge at its tip. How sharp an edge can become is largely determined by the length of that triangle’s sides. In general, the longer the sides (the steeper the bevel), the sharper the edge. Military edges are notorious for having shallow cutting edges that need to be re-angled to maximize sharpness.
Written sharpening instructions have traditionally focused on the aspect of angles. From a machinist’s viewpoint, with a cutting edge immobilized in an end mill and a cutting head that can precisely shave off an exact amount of metal in a single stroke, angles are the measure by which they work.
But it is not a degree of angle that equals a cutting edge. A cutting edge is formed by the apex, or point, the juncture of where two angles come together from either side. That apex is the very definition of a cutting edge, and without it, you do not have a sharp blade, regardless of the angle at which you cut, shave, hone, grind or file.
In general, the steepness of the triangle – the longer the sides leading to its apex – the sharper an edge can be made. This necessitates bevels (the usually flat-ground edges on either side of a blade) being longer. On a wholly flat-ground blade, like Ontario’s RAT knives, its entire sides are bevels, from the full-thickness spine to secondary sharpened cutting edge. Longer bevels are sharper, but they make an edge thinner and weaker, and so are usually relegated to lighter-duty knives.
Knives made to withstand abuses, like heavy machetes and combat swords, have less steep edge configurations, with narrower bevels that leave most of a blade at full-thickness, with a less steep, less sharp apex. This is commonly known as a saber-ground edge. All things considered, a saber-grind is the strongest, most durable, but least sharp of the cutting edges.
Beyond the physical limitations or advantages of the ground edge are variables introduced by the type of alloy a blade is made from, how that steel has been tempered, and especially, how polished the cutting edge has been made. Often a ragged edge feels sharp, but it is, in fact, like a saw, with jagged protrusions that rip rather than cut. A finely polished cutting edge, typically created by working it against a tough ceramic or Arkansas Oilstone honing surface, is just a few molecules thick at its apex, and will cleanly part deer hide (or a heart muscle during surgery) at the merest touch.
In recent years, a number of tools, handheld and power, have been designed to emulate the stability of a mill when a blade is drawn through them. In other words, they’re mistake proof, enabling anyone to achieve a very sharp edge, regardless of sharpening skill.
Pull-through Sharpeners: Based on actual usage, the most popular error-free handheld sharpeners are pull-through types. Made in a variety of sizes to accommodate different settings and applications, these tools generally consist of 2 extremely hard carbide-steel cutters mounted to form a preset V. By pulling a blade through this notch, you scrape steel from its sides until, ideally, a keen apex has been created. A similar notch comprised of ceramic elements smooths and polishes the edge bevels on either side.
The trick to making a pull-through sharpener work for you lies in knowing what to expect. The first pulls will probably feel like nothing is happening; the blade merely slides through from choil (heel) to point. Then the blade will jerk and chatter roughly. Finally, the blade will scrape evenly and smoothly as you pull it through; at this point, running a thumb across the edge (never along it) will confirm that its edge is getting sharp. Usually very sharp.
Fixtured Abrasive Sharpeners: This type of sharpener has changed the game entirely, making every person a honing expert – at least, the ones that work as advertised. This type of sharpener immobilizes a blade using some form of clamping device. An abrasive hone, usually affixed to a sliding metal rod, is adjusted, and then confined to the desired angle by a guide. With blade and honing element thus fixed at a desired angle, all that remains is to apply bevels to either side until they come together at a keen apex. In most instances, these sharpening systems enable anyone to achieve a keen edge on any knife.
The drawback of all such sharpening systems is that they consist of multiple parts, which makes transporting them to deer camp or Thanksgiving get-togethers less than convenient. Most portable of all are the smaller handheld types, like the Aligner Pro from DMT (dmtsharp.com) and Schrade’s Advant-Edge (btibrands.com), available for under $100. The ultimate among this type of sharpener are the Wicked Edge models (wickededgeusa.com), most of which mount to an immovable base for the most precise machine-like cutting edges achievable outside of a machine shop. These latter types range in price from $200 to $1,200.
Handheld Abrasive Hones: Sharpening a cutting edge using a handheld honing “stone” (the tool isn’t always a stone these days) is the skill that every knife owner hopes to attain. In terms of sharpening a blade, this skill is equivalent to having a super power, because mastery of the handheld hone means that the possessor of that skill can sharpen any cutting tool to whisker-shaving sharpness almost anywhere. When I was a field editor for Tactical Knives magazine, writing the monthly Survival and Keen Edge columns, Editor Steve Dick used to joke with me that it really wasn’t fair for guys who could coax a shaving edge onto a knife using a chunk of concrete to evaluate new sharpening tools.
From another perspective, Dick’s jest was confirmation that skill is more important than the tool when it comes to hand honing a new edge. Handheld hones exist in a broad variety of configurations, from aluminum-oxide “stones,” (that are in fact formed in an oven), to natural oilstones, and steel surfaces that have been coated with flecks of industrial diamond. Each of these has in common the need for its users to have developed the skills needed to make it work to create a keen edge. Just as no one is born having the skills of a rifle marksman or a gourmet chef, no one is automatically endowed with the aptitude to sharpen a knife.
As mentioned, written attempts at describing the processes behind hand sharpening have focused almost exclusively on maintaining an exact angle between blade and honing surface. But as sharpening giant Smith’s (smithsproducts.com) has noted, that approach has hurt the cause more than it has helped. A human cannot visually determine, or physically hold, a precise angle while abrading a blade against a honing surface, no more than any of us can tell exactly how many jelly beans are in a jar just by looking.
What we can do is feel when a blade’s edge is making proper contact. Again, disregard everything you’ve heard about maintaining an angle; forward strokes, most useful for setting an initial edge, should appear as if you were trying to shave a very thin slice from the surface of the hone; reverse strokes (away from the edge, e.g. stropping) should drag a cutting bevel along its surface. The easiest honing stroke to master is a simple back-and-forth along the length of a cutting edge. Note that you’ll need to elevate the handle at a slightly higher angle as you round the radius leading to the blade’s tip to accommodate the curvature of its cutting edge.
When first abraded against a rough honing surface (the coarser the hone the better when you first begin), an unsharpened blade will skitter and jerk. Continue to hone. When you’ve established an even honing surface the motion will take on a smoother feel. To a practiced honemaster, this feel is like popping bubble-wrap, almost addictive.
Standard 1095, the original carbon steel, is relatively easy to sharpen; newer harder, tougher alloys, like ATS-34 and D2 require a bit more work to abrade their bevels evenly. If you just can’t seem to get a sharp edge, either you’re honing at an improper angle, or you simply haven’t honed away enough metal to establish a sharply pointed apex – either mistake is common.
When the honed bevels feel as smooth as you can get them against the hone, it’s time to graduate to a finer hone to polish, and sharpen the apex even further.
Master the simple instructions here, and you’ll find it necessary to join the folks who refuse to let anyone else borrow their knives, for their own sakes.
Len McDougall is a veteran survival instructor, licensed wolf-handler, professional tracker, and the author of more than a score of outdoors books, including The Edgemaster’s Handbook, The Scouting Guide to Tracking and The Scouting Guide to Hiking (BSA-licensed handbooks).