Suppose you borrowed H. G. Well's time machine and traveled back into history a few centuries or even a millennium. Suppose, too, that you got stuck there.
The chances are that you wouldn't be able to find work as a handyman. The tools you knew back home in the twentieth century evolved over the centuries, assuming forms almost unrecognizable from those you would observe in the toolboxes of the distant past. But the chisel-well, there you might find a familiar shape and feel.
Stone chisels were used by Neolithic man; bronze chisels were cast in stone by his descendants. From the time of the Romans of classical antiquity up through the nineteenth century, chisels were made of iron, eventually with a thick layer of steel heat-welded onto the working surface. But whenever and wherever your time machine delivers you, you'll probably find chisels of recognizable form that were intended to be used for shaping much as we use chisels today.
Despite the chisel's continuity through time, not all wood chisels are the same. They come in various sizes, and their blades and handles are made differently, depending upon the purposes for which they are intended. In general, chisels are used to trim off unwanted wood while shaping or, in joinery, to give the elements of a joint their final form by shaving off waste.
Most chisels are divisible into two classes: Tang chisels, in which a portion of the blade, called the tang, fits into the handle; and socket chisels, in which a portion of the handle fits into the blade. In theory, socket chisels are to be used with a mallet; tang chisels are not struck, but pushed and guided by muscle power. But in practice these lines are blurred.
There are subdivisions within these two classes, too, most of them named for the uses to which the various tools are put. These names are often omitted or used incorrectly, however, and the confusion is made worse by the variety of trades that use chisels, many of which have their own tool terminology. To a shipwright, for example, the preferred firmer chisel was called a registered chisel; the violin maker uses a purfling chisel. If you were making a gun, you'd probably be glad to have a gunstocker's chisel. You see, a chisel is not a chisel, despite the natural tendency of the uninitiated to think so.
Firmer Chisels. These are all-purpose wood chisels. The name evolved from the French verb for “former,” meaning to form or to shape. It will come as no surprise, then, that this tool is used most often for shaping a workpiece, for cutting away the unnecessary wood to produce the rough form you want. The blade of the firmer chisel is flat, with parallel sides, and typically about four inches long.The handle may be hardwood or plastic and is intended to stand up to the abuse delivered by a mallet. Don't interpret the word mallet to mean any old hammer you have at hand, by the way. Mallets are indeed hammers that are made of wood, but the tools are not interchangeable. When a hammer is used to drive a chisel, the life expectancy of the chisel's handle plummets. Some of the impact-resistant plastic handles on new chisels will stand up to metal hammers, but using a wooden mallet is always a good practice.
If I had to limit my toolbox to a single type of chisel, the firmer chisels would be my choice. These chisels come in blade widths ranging from a sixteenth to three inches, but for most purposes a set of four chisels of a quarter-inch, half-inch, three-quarter-inch, and one- inch widths will be quite adequate.
Heavy-duty firmer chisels, often with hooped handles (in which a metal reinforcement ring encircles the end of the handle) are called framing chisels. They are generally longer, sometimes with blades ten inches long and overall lengths of as much as twenty inches.
Paring Chisels. Paring chisels have thinner, lighter blades than firmer chisels, and tend to be longer than most firmer chisels (seven inches or so is usual). The handle is often of a different kind, too, because a paring chisel is not designed to be struck with a mallet. Rather, the paring chisel is used for finer work, shaving and paring the workpiece, powered solely by the muscles of the hand and arm.
So many paring chisels on the market today have beveled edges that maker and suppliers have begun to identify paring chisels as bevel-edge chisels. They are available in eighth-inch to two-inch widths.
Mortising Chisels. Used for cutting deep mortises, these chisels are designed for use with a mallet. Their blades are thicker to prevent bending when levering out waste.
Butt Chisels. The butt chisel is essentially a shorter version of the firmer chisel. It is designed for use in hard-to-reach or cramped applications.
Solid Steel Wood Chisels. These durable chisels will stand up to mallets and hammers alike. In fact, they are perfect for use at a work-site, as you can afford to be less concerned about their exposure to the elements and careful storage.
These probably aren't the best tools for precise work, but for construction purposes, they are handy and somewhat less expensive. They are sold in various sizes, typically in quarter-inch, half-inch, three-quarter-inch, and one-inch widths.