Planes, saws and chisels form the triumvirate of woodworking hand tools.
Chisels come in a wide range of shapes, sizes and functions. While most building supply stores will carry only one or two styles of chisels, specialty tool stores offer a multitude of choices – framing, dovetail, bevel, skewed, sash, mortise, corner, butt, paring, firmer and gooseneck. Of all these chisels, there are three primary styles that you’ll find in most woodworking shops: mortise, firmer and bevel.
Mortise chisels are heavy, the blades are large and stout and they usually have heavy-duty handles reinforced with steel hoops to prevent the handle from splitting when struck with a hammer or mallet. As the name implies, these chisels are typically used to chop out mortises – particularly deep mortises in hard, dense woods.
Firmer chisels are lighter versions of the mortise chisel (or heavier versions of the bevel chisel) that won’t stand up to heavy pounding with a hammer, but can still be used to chop mortises with a mallet. While you might select a mortise chisel to chop out a 3″ deep mortise on a bed frame, a firmer chisel would be lighter and easier to use when chopping a 1 ¼” deep mortise on a small table leg. Many woodworkers find firmer chisels too large and bulky to use for most furniture making tasks that require light and precise cuts. Furthermore, the square sides on mortise and firmer chisels make it impossible to get into tight corners when cutting dovetails or other intricate joinery.
Bevel chisels are the ubiquitous woodworking chisel, commonly referred to as ‘bench chisels’. They are so named because there are three bevels on the blade. In addition to the one at the front that does the actual cutting, the two long upper edges are beveled back toward the centre of the top giving the blade a triangular form. This allows the tip to penetrate into tight areas, such as when cleaning up dovetails or cleaning up narrow mortises. Bevelling the sides of the chisel removes a fair bit of the metal that stiffens the blade; as a result bevel chisels are generally used only with hand power. Take a look at the handle of a bevel chisel – if the handle has a metal striking cap and is made of a synthetic material, or if it is made of wood with metal hoops fitted to the end, then it is designed to be struck.
You’ll find bevel chisels with both long and short blades. Bevel chisels with long blades typically have a bevel cutting angle of 20º to 30º (compared to the steeper 30º to 40º of a mortise chisel). Short-bladed bevel chisels are called butt chisels and are the favourite of carpenters. They fit easily in a tool pouch and their shallower bevel angle (20º to 25º) make them perfect for hand paring thin shavings or quickly chopping out the very shallow mortise for a door hinge. Many woodworkers hone a secondary 3º to 5º bevel or ‘microbevel’ on the tip of the blade. This strengthens the edge and reduces the time to hone the blade in between sharpening – you only have to hone the microbevel.
Long-bladed bevel chisels are what most woodworkers seem to prefer. They allow a clear view of layout lines because the chisel can be held further up the handle and the increased length of the blade makes it easier to ensure the chisel is being held at 90º to the work. Bevel chisels with long blades make it possible to lay the back flat on the surface of a sliding dovetail to clean out the joint farther in from the edge or to trim off a wooden plug in the same manner.
Sometimes bevel chisels are ground with very shallow cutting angles, of from 15º to 20º, in which case they are referred to as paring chisels. The shallower angle enables them to remove very thin shavings, perfect for when you need to take away just the smallest amount of wood. Typically paring chisels will also have somewhat narrower and longer blades than conventional bevel chisels.
Cranked neck paring chisels have an offset handle that keeps the chisel flat on your work piece, while keeping your hands above the work surface. They are ideal for working in tight places, flush trimming plugs and dovetails, and cleaning up stopped dados.
Just like a hand plane, you will need to fine-tune the chisel before its first use. High-end chisels such as the Japanese bevel chisels from Lee Valley arrive sharp and ready for use right out of the box. Most other chisels will require some work to get them in shape. There are many different ways to sharpen tools and everyone has their favourite. Perhaps the most popular method is to use water stones. A lot of woodworkers like to use a sharpening and honing guide in tandem with water stones.
The Veritas Mk.II Honing Guide or Kell Honing Guide enable you to sharpen and hone chisels quickly and easily. There are also power sharpening systems such as the Veritas Mk.II and the Tormek wet grinding system, which you can use for virtually all your sharpening and honing needs.
Whichever method you use, begin by examining the back of the chisel. In most cases the back will not be flat – the manufacturing process may result in the edge being slightly rounded over at the tip, or it may have faint, though still visible milling marks. Flattening the back is repetitive work, but it doesn’t take as much time as you might think, primarily because you don’t have to flatten the whole back – only about ¾” to 1″ from the tip. And once flattened, you won’t have to do it again for quite some time – until the tip of the chisel is worn down past the flattened area. Once the back is flattened you should hone (polish) it, using progressively finer abrasive grits or water stones or diamond stones. Next you’ll want to hone the bevel side of the chisel. Her is where a sharpening jig really comes in handy, as it will enable you to maintain a consistent bevel angle while you hone.
Fortunately, the steel used in chisels and plane blades today is generally of exceptionally high quality. If you buy a set of chisels from a known manufacturer, such as Two Cherries, Pfeil, Lie-Nielsen, Irwin, Sorby, or Crown, then you needn’t worry about the quality of steel in the tool. Typically the steel will be A2, which is a high-carbon steel alloyed with small amounts of chromium and molybdenum. The hardness of tool steel is measured by the Rockwell scale (Rc). Most chisels are hardened in the range of Rc58 to Rc64. A lower Rc number means the steel will be softer and the tool will be easier to hone but it won’t hold its edge as long, while the higher number implies the reverse. Most manufacturers seem to aim for a compromise between hardness and brittleness, and edge holding ability and ease of honing. Buying Japanese chisels does get a bit more complicated, as they are typically made by individual master blacksmiths. They feature a hard steel layer hammer-welded to a laminated soft steel core. Your best bet is to consult with a retailer who specializes in Japanese tools, such as The Japan Woodworker.
When buying a bevel chisel the most important thing is to hold it in your hand. This will give you a feel for the heft and balance of the tool. For example, while all bevel chisels will come in standard widths (¼”, ⅜”, ½” and so on), they will not come in standard lengths, weights or handle sizes. Many manufacturers have opted for handles made of synthetic materials, often with over-moulded grips. Some handles have round grips, much like broom sticks, others are octagonal in shape, while others have contoured handles with turned finger grips. A chisel should fit in your hand naturally and function as an extension of it. An uncomfortable or unbalanced tool will not be enjoyable to use in the shop.
Buy chisels suited for the task for which they will be used. This is one tool that is advisable to purchase as a set. A typical set of bevel chisels will consist of six chisels in nominal widths from ¼” to 1″. A set of standard length general purpose chisels are ideal for the bulk of day-to-day chopping and paring at the workbench. An inexpensive set of butt chisels are handy for light hand paring work and for when you need to reach into tight spaces. They are also small and light enough so you can carry one or two of them in an apron pocket around the shop or to a job site. For fine work where precise joinery is required, a set of high quality chisels is called for. Using these exclusively for fine work means you can go longer between honings. However, your first set of chisels need not be an expensive set. A basic set will get you off to a good start and then, as your work progresses, invest in high quality chisels as the need arises.
Honing chisels is not as difficult as it may appear at first glance. A lot of woodworkers like water stones because of their ease of use and moderate cost. You can start with three stones. A 1000 or 1200 grit stone will enable you to quickly form a basic edge. Follow this with a 4000 grit stone to get a near mirror finish. If you are looking for the sharpest edge you can get, then go on to an 8000 grit stone. An economical alternative is to purchase a combination stone that has 1000 grit on one side and 4000 grit on the other. Use a stone of the highest grit to put on an optional secondary bevel. It makes good sense to store your water stones in an unclosed plastic container partially filled with water (just below the top of the stones). Add a couple of drops of bleach to prevent mold build-up. Every week or so top up the water. You don’t have to put the 4000 or 8000 grit stones in water. Just splash water over the stones prior to using them. It’s important to keep your water stones flat. The best thing you can do is rub them against a flattening stone after every use. It only takes a minute or two, and you’ll always be ready to hone when needed. Norton makes an excellent flattening stone just for this purpose. If you want to know more about honing and sharpening, check out the Two Cherries sharpening DVD.