First off, I want to start by saying that I don’t consider myself to be an expert in sharpening. I am on the same journey of sharpening skill progression as anyone reading this, and certainly haven’t reached anything resembling a peak. However, I do have a lot of experience sharpening knives. I have sharpened using powered belt systems, fixed angle systems, pull through (gasp!), and stones. Although I think they all have relative merits, except pull through systems (just kidding, they’re simple and convenient and work for some people), I have found freehand sharpening to be the most rewarding. In this article I will tell you what I think are the 3 most integral keys to successful freehand sharpening.
Angle
The angle at which you sharpen the blade has a huge impact on how it sharpens. This might seem self explanatory; the edge is really just the intersection of two planes at an angle and that angle is what allows the blade to separate material. However, I think it is very easy to overlook this aspect of sharpening and make the angle too obtuse or too acute.
Now, I’m not here to tell you what the correct angle is to sharpen your knife. I usually shoot for something between 15 and 25 degrees per side, or 30 and 50 degrees inclusive. That is when and after I have reprofiled an edge, which means to put a whole new angle on. I don’t think most people want to do that as frequently as I do, so it’s more relevant to talk about sharpening from the factory edge.
When resharpening the factory edge, you should try to match the angle from the maker (unless it is terribly thick). A good way to make sure that you’re succeeding in matching the angle is to paint the edge with a permanent marker before you sharpen. After your first swipe on the stone, check to see that the marker was removed across the entire width of the edge. That will indicate that you have matched the preset angle. This technique is simple but invaluable.
Whether you reapex the edge or match the preset angle, it’s important to find the right angle to sharpen. If you sharpen an edge at too low an angle it either won’t actually create a new edge/apex or it will be too fragile, and if you sharpen an edge at too high an angle it will be too thick to cut effectively. Make sure to always start your freehand sharpening by mindfully setting your intended angle.
Pressure
The level of pressure applied is the next of the most important aspects of freehand sharpening. There are two main reasons why it’s easy to put too much pressure into the stone with the blade when sharpening. First, the more pressure you apply the quicker the stone removes metal. This creates the illusion that you will complete the sharpening quicker, when in reality it will create a stubborn burr and extend the overall time cost of the sharpening. It’s a manifestation of our ubiquitous desire for quick fixes, if you want to get all psychological about it. Second, the more pressure you apply the more stable and controlled the blade can feel. When you apply more pressure it seems to hold the blade more securely at the angle, and considering how important that is as discussed above, it can make us focus on the angle at the expense of the pressure.
So why is too much pressure bad? When you apply too much pressure it does two main undesirable things to the edge. First, it leaves deeper scratches that are more difficult to remove/smooth for a good edge. Pushing down hard drives the abrasives on the stone into the metal of the edge resulting in overly aggressive scratch patterns. These tend to be difficult to completely remove and result in a ragged edge. Second, it creates an overly elastic burr. A burr is the thin line of steel created at the apex of the edge that is removed with final honing and stropping to leave behind a crisp apex. When you apply too much pressure it will create a large burr that maintains some of the elasticity of the steel, causing it to flip back and forth from one side of the edge to the other incessantly. This is, for me, the most frustrating thing to deal with when freehand sharpening, but it’s my own fault for getting hasty and applying the excess pressure.
So, how much is the right amount? I have a general rule that I use; if the knuckle of the finger that is on the blade, keeping it stable, is white from applying pressure then it’s definitely too much. Now, that’s certainly not an exact measure and can vary person to person, but it’s an easy way to remind yourself that you might be applying too much pressure. In even more general terms, you should probably go as light as your patience and confidence allow.
Grit
The last key to successful freehand sharpening is a logical progression through grits. This is one that some people might disagree with me on, but I’ve found it to be important for me in my sharpening. The grit of a stone is the size (and sometimes distribution) of the abrasive particles. These can be stone, diamond, or ceramics as well as polishing compounds. Whatever kind of sharpening material you use, it’s important that you start with a lower grit and move progressively up to the highest grit.
The reason it is important to move gradually in progressive steps of grit, rather than just going from a very low grit to a very high one, is because it facilitates a more even scratch pattern and a more smooth edge apex. Without an even scratch pattern and smooth apex, an edge will have too much drag when moving through the material during cutting. This can cause more of a tearing or sawing action than a cut like is achieved with a good edge. All that said, some people prefer a toothy edge. I like a toothy edge sometimes, but I still think a good toothy (and not just jagged) edge requires progression through grits in reasonable steps.
So, what are good grits to use? Well, again, this is somewhat of a wide question. Some people use very low grits like 80 and even 60 on knives, especially if the edge is damaged, but I would save those grits for axes and gardening tools. The lowest I go is 120 grit, but I normally start at 325 grit even for reapexing. I then move up to 600 then a ceramic stone. Ceramics can be difficult to give a grit rating, but it’s probably around 1200. From there I go to a strop with diamond polishing compound, then sometimes I strop lightly on a jeweler’s cloth. As you can see, this shows a pretty much even progression with the grits doubling in each stone change. My system is similar in grit progression to most of the fixed angle systems. For example, the KME system comes with 140, 300, 600, and 1500 grit stones.
All that said, you can still get a more than usable edge with one stone. I’d probably suggest going right down the center with a 600 grit stone, if you’re only going to buy one. The big thing for getting a good edge using only one stone is that you have to focus even more on the first two keys: correct angle and low pressure.
Conclusion
Freehand sharpening can be a very rewarding skill. It allows you to keep your knives sharp with very few tools that can be taken almost anywhere. It also can be a very relaxing practice, almost in a meditative or zen manner. On the other hand, if you fail to follow these keys to successful sharpening it can also be a huge headache! So make sure you practice as much as you can and keep these 3 keys in mind when you do. You’ll be a freehand sharpening champ in no time!
