Chisel is a strong sharp edge cutting tool with a sharp bevel edge at one end. Its construction is composed of handle, tang, ferrule, shoulder, and blade. Chisels are generally made up of high carbon steel. They are used to shape and fit parts as required in joint making.
A gouge is a curved chisel. It may be outside or inside ground. Outside ground gouges are called firmer gouges and inside ground gouges are called scribing gouges. The scribing gouges are made long and thin, they are known as paring gouges. Several varieties of chisels are available, each having special characteristics which fit it for its special use. There are two types of construction employed in the making of chisels named as tang and socket types. The tang chisel is made with a ranged or pointed end which pierces into the handle. The socket chisel reverses the process by having the handle fit into the socket collar on the blade.
Firmer chisel which possesses a blade of rectangular section. It consists of the following parts blade made of cast tool steel and it is used for general bench work. The shoulder of the chisel prevents the tang from being driven farther into the handle when the chisel is struck with a mallet. The ferrule is short length of brass tube (mild steel tube in the case of some mortise chisels) which fits tightly over the lower end of the handle, and helps to prevent its splitting by the tang. The tang is not hardened as to fit in the handle. The handles turned from ash or beech wood as these timbers are resistant to splitting.
Beveled edge firmer chisel
Beveled edge firmer chisel is identical to the firmer chisel except that the edges of the back of the blade are beveled. This enables the chisel to be used for cutting right into the corner of acute-angled wood work such as the base of a dovetail.
Paring chisel has a longer and usually slightly thinner blade than firmer chisel. It may be obtained with a blade of rectangular or beveled edge section and is used in pattern making and where long accurate paring is required. The paring chisel should not be struck with a mallet. This chisel is intended for manipulation by hand only, and not for driving with a mallet like a firmer chisel for cutting of wooden jobs.
Mortise chisel is designed for heavy work. A mortise chisel has a blade which is very nearly square in section and so may be used as a lever for removing chips and will withstand heavy blows from a mallet. Various types of handles are fitted to mortise chisel depending upon use. Mortise chisel has an oval beech handle, whilst the heaviest type of all has a socket handle. This socket replaces the ferrule and affords greater resistance to splitting when used for very heavy work. The leather washer acts as a shock absorber.