Basic Essentials of Sharpening Edged Tools
We’ve all seen it before—the pocket knife that you couldn’t cut warm butter with on a hot July afternoon. It’s a little rusty, the joints are gunked up with who-knows-what, and the only thing it’s good for is opening letters. Almost as bad (or worse depending on your viewpoint) are the kitchen knives that can’t cut tomatoes, that have to be forced through even tender vegetables, and only repeated sawing can get you anything remotely tough.
There’s no reason it has to be this way. I think sharpening edged tools is one of the more useful outdoor skills, and it has a glorious payoff in the home as well. The good news is that it’s no longer a Black Art practiced only by shamans and mountain men who eat only bear meat. The old days of Arkansas stones and a little luck are over. You don’t need to know anything, you just need the right equipment. Let’s start with knives.
There are two basic kinds of edges—plain, straight edges and scalloped, serrated edges. The former are more common, but the saw-like serrated edges are coming into vogue, as they are better at cutting harder materials when a clean cut isn’t as important as a fast one.
The essential sharpening process isn’t rocket science. With an abrasive material, you remove a small amount of metal to restore a clean, sharp edge with enough metal behind it so it stays sharp, and you remove this metal using a low-friction environment so heat build-up doesn’t destroy the temper of your blade.
Different steel grades are used in knives with different functions. Traditionally, stainless steel is more common in outdoor uses because of the ability for it to retain its finish even in damp conditions. However, all stainless steel is not created equal. The carbon content in a stainless blade contributes to the ductile strength of a blade. Ductile strength is basically how much something will bend before it breaks, and in a knife like a fillet knife, think about how brittle would be bad. High-carbon steels tend to have higher tensile strength, and that is a desirable for durable knives, otherwise you’ll be prying a little too hard with your blade on something you shouldn’t be prying on and snap! you’re short one blade.
What you want to find in a good knife is a high carbon content. Super-high carbon content knives are by definition not stainless, but will discolor over time to a dull gray. I happen to think they look beautiful, but that’s my opinion. They do rust if they are kept damp, but a little oil and a little care keeps them from rusting. Goat cheese will darken your knife immediately, so if you want to get a good patina on the blade, just eat a bagel with goat cheese.
Better knife manufacturers use a stainless steel with a higher carbon content. These are better called “stains less” steel, as they will rust if not properly cared for, but are easier to maintain than a pure carbon steel. Grohmann uses a stainless steel with a carbon content that is very high, so the knife blade will last. Less expensive knives (low-end Wal-Mart pocket knives like K-bar, etc.) are low carbon content stainless and will not last under typical use, but then they’re hoping you’ll lose the knife before it breaks.
Knife Sharpening Techniques
Sharpening in years past was difficult; keeping the proper angle on the knife blade so that you had a clean, consistent, flat edge, rather than a rolled edge that dulled quickly. One tended, without any sort of guide, to rock the blade and create an inefficient cutting edge. Tools to keep this from happening are now common. One of the most popular sharpening tools is the Spyderco Triangle Sharpener. It works on the principle that while the human eye has a hard time eyeballing a 16 degree angle, pretty much everyone knows what a straight, right angle looks like. By angling the sharpening media, the guesswork and much of the imprecision is removed and all you have to do is move the knife down the media in a cutting motion toward the base, alternative sides. If you follow the directions, you can shave with the blade of your knife when you’re finished.
I often carry a Triangle Sharpener (it’s wee) when travelling to visit friends. I can usually sharpen every knife in the house in less than an hour or two, and they’re always grateful. It’s relaxing, fun, Zen-like work, requiring little skill but a fair amount of concentration.
Up until a few years ago, sharpening a serrated edge was left to professionals. Sharpen incorrectly and you ruined your knife, usually by grinding down the backside and reducing the amount of tooth in the serrations, or by simply running the serrated blade through a standard (and evil) can-opener sharpener. Despite the cool sound it makes, it’s not a good thing for the knife. The Spyderco sharpener system can do serrated knives, you just have to pretend that each serration is a miniature knife, and treat them with the care you’d treat a regular straight knife. The good news is that serrated knives stay sharper longer.
Okay, now on to axes…
Axes and hatchets are a little different than knives, as usually there is a lot more metal to deal with, and the angle of the edge becomes more important. In essence, if you sharpen an axe with a knife blade angle, it will be extremely sharp, for perhaps fifteen strokes. Axes and hatchets need a little blunter edge so they’ll hold up to the tremendous forces put on them.
This doesn’t mean that axes can’t have a razor sharp edge, though. A good axe is tempered in a different manner than a knife, so more of the metal is harder, but the edge is still soft enough to fine tune. I have cut soft bread with a double-bit axe that could shave a whisker off a mouse, so I know it’s possible. I have pictures, I have proof.
If an axe has been abused and you don’t cut but rather bruise the wood, you’re best to start with a good file, and take slow, careful strokes to reestablish the proper angle and to remove nicks from the edge. Rapid filing doesn’t work any better and it can trash your files. Once you’ve reestablished a nice clean edge, I prefer a tool from DMT (Diamond Materials Technology) that contains a two-faced file-shaped diamond stone that has two grits, a coarser grit and a medium grit. It is the perfect tool for sharpening an axe, and in a pinch, dressing up your knife that you didn’t discover was dull until the middle of the trip.
I know that it’s not strictly an outdoor thing, but there are other tools that benefit from a frequent dressing. My garden tools have a little dressier edge than the neighbors, and they notice my hoes work better, my shovels cut through roots a little easier, and my hedge trimmers cut cleanly. It’s not hard, but it just takes some time.
For the homesteader building a log cabin, I’d consider a DMT Duo-fold stone (as mentioned above) as a must-have in my toolbox. It will take a drawknife from deadly dull to razor sharp with ten minutes and a little elbow grease.
All things considered, a sharper blade in any tool is safer. Less pressure and effort is required, and a sharp blade is more predictable in its behavior. True, you have to pay a little more attention to what you’re doing, but the payoff is in less work and more time to play.
In the book Seven Habits of Highly Effective People , Stephen R. Covey talks about the principle of sharpening your saw. He claims that ten minutes spent sharpening saves twice or three times that in work time and effort. He’s speaking less literally than I am, since he’s talking about taking personal time to recharge your batteries and renew your spirit. Still, if it weren’t a true principle, it wouldn’t make a very effective metaphor, would it?
Bottom line is, use a sharp tool and take your time. As my blacksmith friends say, “The tool works at both ends.” Sure, you’re shaping your world with your knife or axe, but you’re also shaping yourself. Take the time to enjoy the process.