Woodworking 101- Chisels

Introduction to Chisels

The chisel is one of the most widely-used and generally abused tools currently made. Although available in a variety of shapes and sizes, each designed for a different purpose, many woodworkers use only one type of chisel for every job. However, many modern manufacturers have rationalized their ranges to the extent that many special types of chisels are hard to find, so often the woodworker has to make do with what is available.

The chisel performs many functions and, depending on the job, is used in either the left or right hand. Often, the chisel is in use for long periods at a time, and may even be used with a mallet.

Bearing these facts in mind, the chisel must be selected not only for the quality of its steel and the manufacturer's assurance that it has been properly heat-treated, but also for the excellence of its handle design. Too often in the past, chisel handles were made to suit the blade and shape of the woodturning machine, and not of the human hand. Many of these chisels were not only difficult to hold but, with prolonged use, made the hand sore and the arm ache. Fortunately, the present-day manufacturer has paid greater attention to ergonomics, and chisels are designed with not only the hand in mind but also the material used, so that it is comfortable to grip. Many of these handles are practically indestructible, and certainly, most are splitproof. The overall design and color has also been considered.

When looking for a chisel, the woodworker would be well advised to seek out those from a reputable manufacturer. Hold the chisel in both hands, check the handle for firmness and the blade for flatness. At the same time, notice the quality of the grinding, as a badly-ground chisel will require a great deal of work on the oilstone before the fine hairline cutting edge is produced. If a bevel edge chisel is being selected, make sure that the bevels are finely ground. Whilst extreme accuracy of size is not vital, usually if a mortice chisel is bought, it is best to check its accuracy.

Examine the chisel closely to check the alignment of the blade and the handle. Balance should not be ignored, as a thick, heavy-bladed chisel will be out of balance and make working difficult. If the handle is wooden, check it for splits and other flaws. A good chisel, correctly sharpened, will keep its edge for a long time, unless it is abused, so that valuable time is not wasted in resharpening fairly new chisels.

Chisels can be classified under three groups: General Purpose, Mortice, and Special (gouges and knives).

The handles of all these chisels are secured either by a tang or socket, and are made from either wood or plastic. The handles must be checked in the knowledge that they may be struck with a mallet and that often the chisel may be wrenched from side to side. Therefore, the wood must be close-grained and free from knots, and must not be prone to surface cracking and splitting. A hard but pliable wood, which is shock-resistant, is essential. Few of the available timbers have all these features- ash, for example, is fairly hard, pliant, and knot-free, but its grain is quite open. Beech is closer-grained but not quite as pliant.

The early English edge-toolmakers chose boxwood, which is unequalled in its suitability. Boxwood is indigenous to Europe and is regarded largely as a decorative shrub or tree for hedges and gardens. It has a narrow trunk and grows wildly in misshapen branches, reaching about 8' high. The handles are turned from the branches. Box was used by the printer and engraver in the past, and it is likely that these blocks came from trees of some size. The blocks were cut with the grain running vertically, and sold by the cubic inch.

Chisels

Half a century ago, the most widely-used chisel was the firmer. This has a beech, ash, and plastic. It is a general-purpose tool, suitable for most jobs and, as it has a stout blade, can be driven with a mallet if the handle is wooden, and with a hammer if it is plastic. However, the popularity of the firmer chisel has been superseded by that of the bevel edge, as it is virtually identical, and woodworkers are reluctant to buy two chisels which perform the same tasks.

The bevel chisel was designed to cut dovetails - the long edges are beveled to cut the corners of the dovetails. When buying this chisel, the bevel must be checked for a fine edge, as some manufacturers produce chisels with a bevel edge that is too far thick.

All fine cutting can be carried out with the bevel chisel, but it should not be used for deep cutting. Horizontal and vertical paring, chamfering both with and across the grain, dovetailing, housing, stopped housing and dovetailed housings across narrow boards are all well within the capacity of this chisel.

The cutting of mortices is a tough task for a chisel, but luckily a chisel has been produced to combat this. The London pattern sash mortice chisel has a boxwood-handle and a thickened blade which, together with a solid bolster, gives great strength. A leather washer fitted between the brass ferrule and the bolster shoulder absorbs shock.

The steel hooped chisel is another chisel that can be used in morticing. The chisel is of normal length, with a blade thicker than the firmer, but its special feature is a steel ferrule and steel hoop at the end of an ash handle.

A long, thin paring chisel is needed to cut housings (slots against the grain). The blade is thin and beveled on its long edges and has the required reach, as well as the clearance afforded by the bevel. This chisel is the only one which can be used to cut a dovetailed housing. It is available with a cranked, or trowel, neck, which is an excellent feature as it clears the hand from the stock, and ensures the blade lies flat, particularly on very wide work. When selecting this type of chisel, it is vital to check that the chisel is flat across both the width and length. Although slight up-turning of the blade is an advantage, the opposite would make flat cutting impossible.

When paring vertically with a chisel or paring gouge, it is best to work on a cutting board to protect the bench top. One can be made easily from a piece of beech or other even-grained hardwood. If a strip of wood is screwed onto the underside of the board, it can be held in a vice when in use.

A popular chisel among some workers is the butt chisel (or pocket chisel). With the exception of a shorter blade, this chisel is identical to the bevel edge chisel. It is very useful when cutting the housings for butt door hinges.

The swan-neck mortice chisel is used to hollow out the mortices for door locks and other deep recesses. It has beech handle and a long blade with an upturned cutting edge, made of steel.

Another useful tool is the drawer-lock chisel, which cuts lock recesses in drawers and other confined spaces. It has a square-sectioned steel bar with both ends cranked at right-angles and ground to a fine-edge. Once in position, the chisel is struck with a hammer.

Gouges

Gouges which are classified as in-cannel and out-cannel are included in the special chisel group. Cannel is a word which does not appear in the English dictionary, but nevertheless, is a term well-known in the Sheffield chisel industry and in North America.

In-cannel means the cutting bevel has been ground on the inside, and out-cannel means it has been ground on the outside. In- and out-cannel gouges are available as firmer and paring gouges, in a variety of blade sizes and curves. In-cannel gouges with longer blades and cranked necks are also on the market. High-quality gouges have boxwood handles.

The striking of any chisel or gouge, other than the registered pattern or drawer-lock chisel, should be done with the joiner's mallet. This has a handle of pliant ash, the head is best made from Danish beech, and the handle socket is tapered to ensure a tight fit.

Knives

Another edge tool which is vital in the workshop is the knife, because it is needed to mark out lines which have to be cut either with the saw or chisel. The woodworker can choose between knives with blades ground on one side only, or on both, and with wooden or plastic handles. Knives needed for other work are available in various shapes.