Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 126

THERE is a great variety of boring tools, and apart from the important question of size, there is that of suitability. Bradawls are well-known and useful tools for soft wood. The stem is cylindrical, and the chisel edge cuts the fibres, and the wedgelike form of the tool pushes them aside; used in end grain, it scrapes and pushes its way in, and, roughly though effectually, it makes a hole for, a nail or a screw. The bradawl can be used for hard wood, but its special use is for soft wood, and its province is limited to comparatively small holes. In hard wood it has to be turned right and left more freely than is necessary in softwood, the edge acting more like a scraper in the harder material. The great limitation of the bradawl is that there is no provision for the waste material, and so it can be used for small holes only. The ordinary form of bradawl is shown by Fig. 360, and a larger kind, the flooring awl, by Fig. 361. These may have handles of ash, beech, or boxwood. The patent brass-capped bradawl (Fig. 362) is an improvement on the ordinary form. In the old bradawl the tang of the blade is driven into the handle, and a semblance of strength given to the tool by a brass or iron ferrule; but occasionally, when attempting to withdraw the bradawl from a piece of hard wood, handle and blade may come apart, the handle remaining in the operator’s hand and the blade in the wood. In the brass-capped bradawl (Fig. 362) the end of the handle is so fitted into the brass cap replacing the ferrule that the blade is secured in the handle so firmly that they cannot come apart in the manner described above. When the handle of the ordinary awl parts from the blade, the latter is removed from the work by means of pincers, with the risk of bruising the work or perhaps breaking the bradawl in the hole. Therefore it is very necessary to guard against the bradawl coming apart and so the following method should be adopted: First, the steel tang of the bradawl blade is to be softened at the extreme end by making it red-hot in a gas flame. When allowed to cool gradually it will be found to be softer and tougher than before. The softness is not to be confined to just the extreme end, but very great care should be taken not to draw the temper of the cutting part of the tool. Mark the length of the tang on the bradawl handle, and at 1/8 in. from this mark towards the end where the shoulder of the awl comes, bore a hole at right angles, or nearly so, with the tang. The tang of a bradawl is usually, and should be always, oblong in section. Bend the tip of the tang slightly, and insert it in its handle. Now by judiciously driving a brad into the hole previously bored (see Fig. 363) the slight bending of the tang can be increased to form a hook, while the brad makes the bent end embed itself tightly in the handle. Finally, the brad is filed off at both ends, and given one or two riveting blows (see Fig. 364). A bradawl so treated, if done well, will not come out of its handle, and will last until either blade or handle is broken. Care must be taken that the tang is driven only just past the hole bored for the brad, and the brad driven to increase the bending of the tang. For this purpose, when the bending is sufficiently started, it will be best to drive the blade home and then the brad; but if the tang is inserted too far when the brad is driven, instead of increasing the bend the brad will diminish it, and the desired effect will not be produced. The method of boring a hole with a bradawl is shown by Fig. 365, the edge of the awl being across and not in line with the grain of the wood.

Fig. 360.—Bradawl.

Fig. 361.—Flooring Awl.

Fig. 362.—Brass-capped Bradawl.

Fig. 363.—Fixing Bradawl Blade.

Fig. 364.—Bradawl with Fixed Blade.