The simplest form of boring tool is the awl or bradawl as it is more generally called, Fig. 374. It consists of a piece of small steel rod, with one end fastened in a wooden handle, and the other doubly bevelled to a sharp edge, which serves the purpose of compressing and displacing the fibres of the wood so as to form a hole without producing any chips or dust from the wood operated on. Its greatest drawback is the readiness with which the awl proper may be pulled out of its handle in withdrawing the tool from the hole it has made, especially in the case of hard woods. Superior awls are, however, made to overcome this fault, the handle being hollow and containing a selection of awls of different sizes, each fastening into the handle by means of a screw-nut. The use of the awl is to prepare holes for the admission of nails and screws.