Sharpen Up! Basic Essentials of Sharpening Your Edged Tools

by Darren Bush on August 11, 2011 · 32 comments

in Manly Skills, Toolmanship

This post is part of a series brought to you by RAM. For more information about RAM Series trucks visit us at: http://www.ramtrucks.com/en/guts_and_glory/. What’s this?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, or anything remotely tough without repeated sawing.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 an art practiced exclusively by mountain men who eat only bear meat. The old days of nothing but Arkansas stones and a little luck are over. It’s really not hard at all; you just need the right equipment.

Let’s start with knives.

Sharpening Knives

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, and you remove this metal using a low-friction environment so heat build-up doesn’t destroy the temper of your blade.

This isn’t meant to be a piece on metallurgy.  There are people way geekier than I who can give you a lesson on the finer points of the hundreds of different alloys with their various properties.  It’s just about sharpening stuff.

My preference in a good knife is a high carbon content. Super-high carbon content knives are almost always 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 slice off a hunk for your bagel.

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 they’re easier to maintain than a pure carbon steel. Knife companies like Benchmade and Grohmann use a stainless steel with a carbon content that is very high, so the knife blade will last. Less expensive knives (such as low-end Wal-Mart pocket knives) 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.  Most people do.

Techniques

Sharpening in years past was difficult, as it necessitated 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.  A master carpenter could free-hand an angle like a machine, but most of us can’t.

Tools to keep this from happening are now common. One of the more popular sharpening tools is the Spyderco Triangle Sharpener (and others of its type). It works on the principle that while the human eye has a hard time eyeballing a 21 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, alternating sides. If you follow the directions, you can shave with the blade of your knife when you’re finished.

I had never tested the angle of the Triangle Sharpener.  I used a level to get a good reference for the bevel gauge, and referenced off that (I know it doesn’t look plumb…I promise it was).  As you can see from the picture, the angle of the sharpener is just over 20 degrees. That’s a good angle for most tasks.

I often carry a Triangle Sharpener (it’s wee) when traveling 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.

Another approach is to lock down the angle using a guide. One such type is the DMT (Diamond Materials Technology) sharpening system, which uses a clamp-on guide to make sure you keep a consistent angle.  You can choose an angle depending on the type of edge you want.  The lower the angle, the sharper you can make an edge, but it is a less durable edge.  Scalpels can be used for surgery, but they’ll dull in seconds if you try to cut something other than flesh.  A meat cleaver wants a higher angle, because you want a durable edge, even if it’s not razor sharp.

The first picture's a little cluttered, so I added a visual cue so you can spot the angle more easily.

Here’s sharpening in action with a Spyderco:

There are times when you must free-hand things.  In the case of the venerable crooked knife, the curvature of the blade makes it impossible to do the sharpening with a guide of any sort.  It requires a little practice, but as you can see, it’s doable and it works.  I just use one of the ceramic rods from the sharpener.

Here’s a quick little video of sharpening a crooked knife:

What sort of edge do you need?

A razor, fillet knife or X-Acto generally wants an angle under 17 or so. Chef knives or other precision knives often center around 20 degrees, more or less.  Survival knives are usually over 25, because they want to be able to hack as well as cut. Over 30 degrees you’ll see machetes and cleavers.  For most knives, I choose around 20 degrees.  It’s a good compromise.  I’ll go slightly smaller in a blade for skinning, slightly higher for knives that’ll get more everyday use.

Axes and Other Potentially Sharp Things

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 is higher–more like a cleaver.

A good axe has the same quality steel (though not the same alloy) as a good knife. But don’t try to make an axe razor sharp. If you sharpen an axe with a knife blade angle, it will be extremely sharp for about ten strokes. The first few chops will take off that edge, and your careful sharpening will have become a waste of time. Axes and hatchets need a little blunter edge, so they’ll hold up to the tremendous forces put on them.  The one exception to this rule is when you do it for fun.   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.  It’s also fun to shave with an axe as a proof-of-concept.  I’ve done it once, but stopped short around my nose and ears as I like them very much and want to keep them.

If an axe has been abused and you don’t cut but rather bruise the wood, it’s 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.  More on that later.

Once you’ve reestablished a nice clean edge, I prefer a tool from DMT that contains a two-faced file-shaped diamond stone that has two grits, a coarser grit and a medium grit (the black and blue-handled one). 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.

Axe Sharpening Techniques

Here is a wood splitter with an abused edge–big chips.  Before I can really sharpen it, I need to establish a new clean edge.  It might seem weird to file an edge flat before trying to sharpen it, but it’s necessary.  The next step is to establish an angle.  30 degrees or so works for most axes.  Like the Triangle Sharpener, it’s easier for a person to see a right angle.  What I do is set the piece so that the angle needed is parallel to the ground.  Then I start with the file work.  Here I’m using a splitting wedge that I rescued from an unmarked grave after the power company left it in the yard at least a decade ago.  I used a level to make sure the face I wanted to cut was parallel to the ground.

A file is a precision tool.  You can get a file for $5.00 at Harbor Freight (don’t), but a good file costs more and is worth it.  Like a good knife, a good file needs care and should be treated well.  A file only cuts in one direction, and that’s on the stroke away from you as you push.  Dragging the file back and forth isn’t good for the file, and you have less precision.

As you stroke away from you, the file should feel smooth and not be jumpy.  If you feel something that feels like it’s caught between your work and the file, something is. Stop and clean your file with a file card or small wire brush.  If you look at the surface of the edge you’re filing, it should be smooth.  If your work looks like your windshield when a maple tree seed gets caught in the wiper, you’re messing up your nice, smooth surface.  You really want to see a long, flat face, not several bevels.

This is pretty good…but there are a few flaws to point out.  On the edge closest to the bottom of the picture you’ll see a little facet that shouldn’t be there, caused by a moment of inattention.  Not fatal, but I wanted you to see what it looks like wrong.  Second, you’ll see some scoring in the edge parallel to the bottom of the picture.  That’s caused by a bad file, a dirty file, or both.  Easily cleaned up by using a diamond stone, but it takes more time the deeper the scoring.  I used an old, abused file.  Time to make some strikers.

Once the edge and angle is established, finish the work with a DMT Duo-Fold.  There are four grits commonly used, as seen in the picture.

Red and green are fine and superfine; blue and black are medium and coarse.  They fold up on themselves nicely and take very little room.

If a blade or other tool has been abused (it happens a lot with cheap axes and splitting wedges), after sharpening a tool I’ll protect it with a compound I create myself.  This is a secret formula, with carefully-hidden ingredients.  It’s a good thing no one knows about my 9:1 ratio of linseed oil to beeswax, melted and mixed and applied to metal then wiped and buffed a little with an old t-shirt.

Other Tools

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 your toolbox. It will take a drawknife from deadly dull to razor sharp with ten minutes and a little elbow grease.

About Safety

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.

{ 32 comments… read them below or add one }

1 Fulano August 11, 2011 at 2:20 pm

Great article!

There was a minor point that you missed that is important for sharpening hoes and other tools – sometimes it’s better not to sharpen both sides of the blade.

If you leave one side flat it will change the way the blade bites. For example, on a hoe you want to sharpen the side closest to you as it will help the blade bite deep. Sharpening the far side will make it tend to cut shallower, which is great for a whittling knife, but not so much for a hoe or pick.

2 Eric August 11, 2011 at 2:41 pm

I’m a fan of using sandpaper attached to glass, backed by MDF for sharpening my wood shop tools and kitchen knives. Ranging from 220 grit up to 3600 grit, you can put an AMAZING edge on your blades.

3 jweaks August 11, 2011 at 3:41 pm

A leather strop loaded with rouge (yellow type best for most blades) is one of the easiest and best ways to keep a knife super sharp.

Don’t remove metal with abrasive sharpening techniques unless you have to, to get it to a good basic sharp.

jw

4 Phil August 11, 2011 at 6:43 pm

I’m sure it’s the topic of another article, but it should go without saying that once you’ve put in the effort to get a nice sharp knife, use that honing steel you’ve been ignoring in the knife block so you don’t have to break out the sharpening tools again for a long time.

I’ve got a couple of decent kitchen knives that have never seen a sharpening beyond what God gave them at the factory six or seven years ago, but still slice paper-thin tomatoes at five paces because I am a good boy and give them a few passes on the steel before I start in on making dinner.

Another good article would probably be in how to choose knives that aren’t junk and so will last long enough to eventually need a sharpening. Short version of this article: if it’s “as seen on TV” or features “micro-serrations”, please don’t buy it; you will only frustrate yourself and any friends who come over to cook dinner at your house. My church, sadly, is the poster-child for ignoring this rule. When we’ve got a dinner planned there, my first step is to roll 3 of my knives up in an apron and get them ready to bring with me because they’re going to be the only ones that will cut butter without having to heat the butter first.

5 Brian August 11, 2011 at 10:32 pm

Great article.
“…a double-bit axe that could shave a whisker off a mouse, so I know it’s possible. I have pictures, I have proof.”

How did you get the mouse to hold still? I’d like to see the pic. : )

I just picked up a Spyderco Triangle Sharpener. It’s far easier than an Arkansas stone but it still takes doing a couple of knives to get a feel for it. I don’t recommend starting with your best knives. My kitchen knives and pocket knives are now razor sharp. Now I need to get a strop. Eric’s method is also known as “The Scary Sharp” method. I use a piece of glass for the backing and attach the sandpaper with 3M photo adhesive spray. It will put a razor edge on a chisel. I was going to try it for my knives but I can never hold them at a consistent angle.

6 caleb August 12, 2011 at 12:27 am

Lansky makes some awesome sharpeners that work very quickly. The only problem is that the angle changes slightly if you do not line it up exactly. I recommend the diamond 3 pack. http://www.lansky.com

7 Lucas Denton August 12, 2011 at 1:05 am

Kabar knives are not cheap walmart knives. Thier 1095 Crovan steel keeps a hell of an edge. You obviously have no idea what you’re talking about.

8 Andrew August 12, 2011 at 3:21 am

A great way to put that final razor sharp edge on your knives is to use your car window. After you finish with the fine stone, roll your window down a bit, and run the knife on the edge of the window at the proper angle. I do 8 on each side, then 8 strokes alternating.

Credit to Ray Mears.

9 Hoss August 12, 2011 at 8:37 am

Knives require only three things to stay sharp: a whetstone to sharpen, a butcher steel to hone, and practice. Period.

Mower blades, axes, hoes, sickles and shovels ( yes, sharp shovels dig easier than dull ones) need only a file to smooth large burrs and the same whetstone your use to “rough” the knives is used to “finish” the hone on outdoor tools.

For extra cutting power on soil engaging edges like hoes, shovels, or pickaxes, I normally notch the edge with the corner of a file, about every half inch along the cutting edge. It’s like teeth on an excavator bucket and helps the edge “bite” more easily into heavy clay or dense sod. Don’t do this for knives or axes, but only for soil engaging edges.

10 David H. August 12, 2011 at 9:25 am

Is there an article on how to pick the proper ax, shovel, or other garden tools?

11 Aaron V. August 12, 2011 at 10:38 am

Fun fact: Sharpen the claw on your hammer to make pulling nails and just generally tearing stuff up 100% easier.

12 Adam H. August 12, 2011 at 11:36 am

It seems a bit strange to me that you would pick Ka-bar to single out. While it is true that they have some knives that run in the .5 carbon range, namely their smaller low price knives, they still hold a decent edge and provide a long life. The heat treat is the most important aspect to consider here, the steel just determines the proper heat treatment. That being said, Ka-bars higher end knives run in 1095 and a 1080 equivalent, yes the high carbon steels you praised. Most every knife company has multiple tiers of quality and Ka-bar is no exception.
I apologize for singling out that comment out of a well written article. I currently sharpen my blades on a plate of glass with automotive sand paper. Works well, and on my single bevels it leaves a very smooth surface. I’ll have to try out one of those triangle sharpeners. If they’re as good as you say, I may be able to teach my mother to sharpen her kitchen knives.

13 Darren August 12, 2011 at 12:01 pm

@Fulano — yep, didn’t mention that. That’ll be covered in the next article when I talk about drawknives, planes, spokeshaves, etc. Good call. I use a plate with 1000 and 1600. Good enough for my purposes.
@Hoss — you’re absolutely correct, if you have a lot of time and a lot of blades and you want to invest the time. The key word in the title is Basic.
@Eric – that’s how I sharpen my chisels and plane blades.
@Caleb and Adam — Probably a bad choice for an example. Case, Schrade and a few other notable companies make some good knives, but the line is inconsistent. I have no problem changing that to “generic Wal-mart knife.” And you’re right, I don’t what I’m talking about.

14 Larry August 12, 2011 at 12:04 pm

I do some woodworking and I am very proud of my chisels, skews, gouges and Plane blades. they will shave your knuckle hair or peel a finger nail. Knives are a whole ‘nother thing. I struggle to keep them useable! I am working on it though. Your article helps. I am considering breaking down and getting a jig of some sort, something I have never felt the need for with chisels.
One other thing, handwash the kitchen knives. My wife keeps putting them carelessly in the dishwasher. She has been told this is one of the few things that warrant physical abuse, but she knows I am kidding and tends to ignore my pleading.

15 Harry August 12, 2011 at 12:18 pm

I can vouch for the Spyderco sharpening set – I’ve used one for years with great results, and it comes with instructions on sharpening just about anything.

Also, if you are really in a pinch and the knife is too dull to use, the bottom of a ceramic coffee mug, the ring where it’s rough and not glazed, can be used.

16 Will August 12, 2011 at 3:16 pm

Well written article. I just want to say I love the fact that you mention Grohmann knives. I love the style of Grohmann blades and they have fantastic quality but for some reason you don’t hear as much about them. Plus I like the fact they’re made in Canada. :)

17 Dwight August 12, 2011 at 4:10 pm

“Better knife manufacturers use a stainless steel with a higher carbon content.”

Better knife makers use the best steel for the job with the proper heat treatment. Carbon or stainless steels have too many variations to make a blanket statement like yours. 440 stainless has many variations. Some make great knives some make OK knives. 440A, the lowest grade, can make a good knife if the maker does his part correctly. It will never equal a knife made of a better tool steel.

Whatever the steel proper care is essential as you pointed out.

18 pete August 13, 2011 at 4:07 am

As a professional chef; I find that half an hour with a good oilstone every two months or so and frequent visits every day with my trusty diamond steel keep my blade razor sharp.

@Larry: my knives have never seen the inside of a dishwasher, and forgiving your wife for what she did was truly a manly act.

Something that really baffles me is the number of want-to-be cooks that I’ve seen come and go, who don’t even know how to care for their most important tools, their knives.

Really, what’s the point of owning something that you don’t know how to care for? When your primary tool for ten to twelve hours a day is a knife, wouldn’t you think you should know how to keep it sharp?

19 Rob August 13, 2011 at 9:05 am

As a carpenter I know this area well. I could spend hours sharpening all the things in my shop, so I always look for quick ways to get things done. The Spyderco method works great for basic sharpening of kitchen knives. That being said, about once a year the basic bevel needs a substantial re-do. I use a bench grinder with norton wheels. I threw away the basic bench grinding wheels long ago because they generate too much and the blade loses its temper(hardness). It takes a little practice to get the bevel right, but it can re-do a bevel in no time.

20 Hal August 13, 2011 at 12:40 pm

Good article for the basics. I also like the sandpaper method for a lot of things. Sometimes I put a soft backing under the sandpaper to give a convex edge (which can be useful at times). As for the axes, they need to sharpen differently depending on what you’re using it for. A felling ax will need to be as sharp as you can get it, since you’re cutting across the grain. Yes, you’ll have to resharpen it more often, but you can keep the edge much longer if you avoid knots, dirt, and other things that will screw up an edge. If you’re using it for limbing, you’d want a slightly thicker edge, as it will more likely encounter knots and such. For splitting, you want a pretty obtuse angle.

As for the steel, I won’t go into the metallurgy (what I do for a living), but I will say that the heat treatment is far more important than the alloy. If you take 420HC (what Buck mainly uses) and give it a good heat treatment (which they usually do), you can have a blade that will outperform a poorly heat-treated 440C (a very popular and very EXCELLENT steel alloy for knives). Softer steels aren’t necessarily a bad thing, though. A lot of really hard alloys with heat treatments designed to make them even harder can be a real b—- to sharpen with anything but a diamond stone. The ability to sharpen it on any ol’ Arkansas sometimes makes up for having to touch up the edge it in the middle of quartering a deer.

In general, not a bad article. An article on basic sharpening doesn’t need detailed metallurgical details or obscenely close-up images of various edges to be effective. Keep the angle consistant and use the knives in the manner they were intended to be used (i.e. cutting things, and not prying things), and things will be just dandy.

21 Hal August 13, 2011 at 4:31 pm

If you’re wanting all the detailed metallurgy, heat treatment, and technique information (along with many magnified images of edges), an excellent book is Leonard Lee’s book The Complete Guide to Sharpening. I highly recommend it.

22 P.M.Lawrence August 14, 2011 at 1:14 am

… my shovels cut through roots a little easier …

I think you’re confusing shovels and spades, which are not the same thing at all. A shovel is a scooping instrument used on loose material, with a raised rear and sides and a broad blade shape to reduce spillage, a short handle to keep the load near the lifting, and no cutting edge or foot bracing rear as they aren’t needed. A spade is a digging instrument used on firm material, without raised sides and with a narrower blade shape to reduce resistance, a long handle to provide leverage to pry material loose, and a cutting edge and a foot bracing rear to get into the material. They are very different, in much the same way and for the same reasons as a soup spoon is different from a dessert spoon. Avoid digging with a shovel if at all possible. Like a cleverly made plough, a regularly used spade with the right tricks used in making it will effectively self-sharpen just from cutting the earth (they make the metal nearer the edge a bit harder).

Brian asked of “… a double-bit axe that could shave a whisker off a mouse, so I know it’s possible”, “How did you get the mouse to hold still?”

That’s obvious – you hit it with the axe.

23 Brad Smith August 14, 2011 at 11:51 am

I came across this site on LewRockwell and I have to say it’s just fun to read. As for sharpening things, It’s good advice. I just don’t see why it’s so hard for people to get the angle down? I tried to teach my father for 25 years, nope not going to happen. My wife got it, but not dad.

Keeping anything sharp is part of safety. Anything dull is dangerous. From chainsaws to knives and everything in between. Keep them sharp and you will be much safer.

24 Dale August 14, 2011 at 7:52 pm

Very useful for me – I was literally just whining to my wife about the dull edge of my axe and hatchet this AM after trying (unsuccessfully) to remove a tree root… Thanks!

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26 David T August 15, 2011 at 4:49 pm

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27 Chris N. August 27, 2011 at 2:56 pm

Good article, but I would emphasize that freehand sharpening on a whetstone is a fine task. One which will also hone those skills so often required for true manliness: Patience and Perseverance.

28 Hal August 28, 2011 at 10:36 pm

Another great book is D.Cook’s “The Ax Book”. Lots of info about properly sharpening axes and saws for various uses on various kinds of wood.

29 Bogdan September 4, 2011 at 8:03 am

Hi. Any idea how long the Spyderco sharpener’s stones last?

30 jerry February 17, 2013 at 1:21 pm

hoss…period!

31 ralph February 23, 2013 at 9:07 pm

Please note top comment. The picture of a sharpened hoe in this article shows a hoe sharpened on the incorrect side!

32 Matthew April 8, 2014 at 1:38 pm

Glad to see you recommended the Spyderco Sharpmaker. It works awesome for pretty much any type of knife. It’s far more intuitive than a whetstone and I find it easier for an inexperienced person to put a really nice edge on a blade.

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