What better place to start than with sharpening? Sharpening is one of the most important skills to perfect and put into practice regularly. Sharp tools are not only safer than blunt tools but they also produce much better results and make working with them so much more enjoyable. A sharp chisel will be able to shave the hair off your arms and pair the end grain of soft wood without tearing it but rather leaving a shiny surface.
There are many different ways to sharpen your tools but one of the oldest and best methods is on waterstones. They may not be the fastest option out there but with a little bit of set up it doesn’t have to be a slow process.
When two faces of a blade meet they create an edge, the sharpness of that edge is determined by how finely they come together and how fine the scratches on the faces are at the meeting point. In the same way that sanding removes large scratches for smaller scratches as you work up the grits, sharpening with higher grit stones creates smaller scratches which can create a mirror finish and razor sharp edge.
The first step in achieving a razor sharp edge is to make sure your stones are dead flat. This can be done by rubbing the stones on a piece of sand paper stuck to a piece of float glass or on a measured flat diamond plate, the latter being more expensive but superior as they are generally more flat than float glass.
The second step (and most time consuming) is to make the back of the chisel flat with a mirror finish. This process can be slow depending on the size of the chisel, how hard your chisel steel is and how out of flat it is. Start by rubbing the back of the chisel on about a 1000 grit stone to see how bad it is, if it’s only touching in a couple of spots move down to the lowest grit you have, I use a 220 grit stone. Ensuring that the chisel is kept flat on the stone at all times rub it back and fourth going over the whole stone. Work your way up through the grits, making sure that all the scratches from the previous grit have been removed before moving onto the next. Note that if all of your stones aren’t perfectly flat this process is going to be very frustrating and slow, make sure that step 1 is done correctly first. How fine in grits you go is up to you but I would recommend 4,000 as a minimum. Somewhere around 6 – 8,000 is better. My finest stone is 12,000 grit which some might call overkill but I like my chisels as sharp as possible. Higher grit stones start to get fairly pricey so if you’re starting out or on a tight budget it might be best to stick to around 4,000. My stone grits are 220, 1,000, 4,000, 8,000, 12,000. Once you’ve done this step properly you shouldn’t have to do it again for the life of that chisel as when you go to re-sharpen down the track you’ll only have to touch the back of the chisel on your finest stone once you’ve honed the bevel through the grits. Don’t ruin all your hard work by introducing deeper scratches again.
The last step is to hone the bevel of the chisel. When learning to sharpen on waterstones I think that it is best to learn how to do so by hand first. That means creating a hollow grind with a grinder to give yourself 2 reference points to rest on, then hone the chisel on the stones by locking your wrist into position and moving the chisel in a back and fourth or figure 8 motion ensuring you utilise the whole surface of the stone. Having this skill is never going to hinder you, however not having it may make sharpening odd shape tools more difficult down the track. As much as I was initially against it, I now use a honing guide to sharpen my chisels. The honing guide allows me to repeatedly get the exact same angle, makes honing much faster and means that I don’t have to ever touch my expensive chisels on a high speed grinder with the potential of bluing the metal and grinding off more than I need to, shortening their life. I use a primary angle of 25° which I can grind on my 220 grit stone using a honing guide. I then hone a secondary bevel at 30° giving me a razor sharp edge. This method also means that I don’t have a hollow grind, meaning that there is more steel right behind the cutting edge, keeping it stronger and less prone to breaking under heavy blows.
To make the sharpening process really fast I’ve made a jig that my stones are held into and on the edge it has a guide for how far the blade needs to protrude to get a particular angle. I can then have a dedicated sharpening area where I can go to sharpen very quickly when required. Or if space is an issue, the board that holds the stones can easily be stored on shelf and pulled out when required. It’s important to make sharpening as easily accessible as possible so that you don’t put it off and work with blunt tools.
There is a lot to cover in sharpening, let me know what I’ve forgotten about. How do you sharpen your blades? Comment any questions you have regarding sharpening your tools for wood or email me if there’s another topic you’d like me to cover.