Hand chisels are a very refined tool that need great care. They are known for their sharp edges and precision cuts, but you also have to know how to care for these tools too. A blunt chisel will never perform the way you need a good chisel to perform. Additionally, safety with blunt chisels is always a concern. A blunt chisel is an an even more dangerous instrument than a sharp one because it can leave wounds so jagged that it takes forever to heal. Taking all of that into consideration, you should learn how to sharpen your hand chisels properly (if you do not have them professionally sharpened and want to sharpen them yourself). There are two methods to properly sharpen your chisels.
The Honing Jig Method
A honing jig is a device that sits on top of a whetstone and acts as both a stabilizing clamp and a an angle perfecter for the chisel blades. Some honing jigs are adustable, using a turn-screw clamp to lower and lift the angle at which the blades meet the whetstone. The top part of the jig has a slot opening where you insert the flat chisels, beveled edges down. The jig clamps onto the chisel so that the chisel cannot rock, pivot or even turn slightly on edge, which would cause the wrong surface to be sharpened, or worse, cause the chisel’s corners to be chipped off and damage the tool.
To sharpen a chisel with the jig, set up the jig and whetstone according the instructions on/in the jig’s package. It should always be sitting on the most level and flattest of surfaces, such as a workbench, but the workbench has to be really sturdy and not wiggle either. Once the jig and stone are set up, you can slide a chisel into the jig’s stabilization slot at the top and tighten the screw clamp down so the chisel does not wiggle. Now you just oil or whet the stone and push the jig forward. As the chisel blade makes contact with the stone and is pushed against it, it sharpens.
The honing jig method is definitely preferential to bare-facing the stone and praying you do not damage the tool because you are not using a guide. It is also much safer, because there is less of a chance of the chisel slipping and slicing open your fingers or hands. If you have NEVER sharpened a chisel before, DO NOT use any other method to sharpen your chisels until you have used a jig and gained lots of experience from its use. Eventually, you will get a good feel of how the chisels are supposed to be angled and honed, and then you can try the next method listed below.
Just You, the Chisel and the Whetstone
Most professional woodworkers and wood carvers who have spend years using chisels have become accustomed to feeling out that exact moment when their chisels are getting dull and ineffective. They also know exactly how to sharpen their chisels without using a honing jig. They have learned through their experience how tightly you have to hold a chisel and how very careful you have to be when slicing it across the bare-faced whetstone. (If you do not have the hands of a surgeon, do not use this method EVER.)
If you are past the honing jig phase of your chisel sharpening days, and you think you are ready to take on this method, you might want to do two things first.
- Start with your cheapest and most poorly-made chisels. If you screw up the blades on these while you are learning to sharpen without a jig, the loss isn’t as bad as if you were sharpening a chisel that cost you $150. Sometimes the pain incurred with sharpening chisels is less about cuts to the flesh and more about cuts to your wallet.
- Learn which types of whetstones and lubricants to use with which chisel blades. If you are sharpening titanium blades, you may want, need or prefer diamond whetstones. There are also various grits of stones, which are meant to help you sharpen and refine the blades but can also damage your blades faster if you slip or do not stabilize the chisel well.
That said, prepare your whetstone as you would normally for sharpening chisels. Then examine EACH chisel before you set it to the stone. You want to make sure you are not changing the angle of the bevel of the blade by setting it against the stone at the wrong angle. If the bevel is 35 degrees, you have to set and keep the bevel blade at that angle before, during and after you sharpen it. There are accessories that can help you determine the angle of each blade, but some of the better chisels may also have it inscribed on their handles.
Next, you have to place the chisel in your hands, brace the butt end of the chisel against your body or the heel of whichever hand you place over the top of the other. (Lefthanders, this is your right hand, and right-handers this top hand would be your left.) Mimicking the correct angle of the beveled blade, place the chisel’s blade end against the stone and push forward. Lift up once the blade reaches the end of the stone. Examine the blade to make sure you didn’t shift, wiggle or change the angle as you pushed. Repeat, repeat, repeat, until the blade edges are sufficiently sharpened. A very, very slow and steady hand is how its done.