The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking. Paul N. Hasluck
href="#ulink_17313ac4-45ff-5b16-95e3-651a7b9663bf">Fig. 355) used in an ordinary brace. It is chiefly useful where many large or medium-sized screws are required to be driven. The power gained is considerable, owing to the length of lever afforded by the sweep of the brace, and it has the additional advantage that the entire weight of the workman can be applied to keep the driver in the screw-slot without decreasing his power of turning as in the ordinary pattern; it is also very speedy, as the turning is continuous. The ordinary screwdriver may be found in the way when screwing a lock on or off, inside the front of a drawer, as this is generally done with the drawer in position. The short screwdriver illustrated by Fig. 356 is well adapted for work of this description, and the handle being broad and flat is convenient to hold in the hand. Another short screwdriver is shown by Fig. 357, and this is designed especially for unscrewing plane irons, as shown on p. 45, Fig. 163.
Fig. 349.—Plain Handle Cabinet Screwdriver.
Fig. 350.—Oval Handle Cabinet Screwdriver.
Fig. 351.—Fluted Handle Cabinet Screwdriver.
Fig. 352.—Spindle Blade Screwdriver.
Fig. 353.—Gimlet-handled Screwdriver.
Fig. 354.—Brace Screwdriver in use.
Fig. 355.—Screwdriver Bit.
Fig. 356.—Short Screwdriver.
AUTOMATIC SCREWDRIVERS.
The automatic screwdriver is made in variety, but the principle of all is much the same. The blade of the screwdriver, which is cylindrical throughout its length except for about 1 in. at the point, where it is flattened so as to enter the slot in the screw head, works in a hollow handle partly of brass and partly of wood. In using it the blade must be drawn out to its full length, and inserted in the slot of the screw, which is then driven home by pressure on the top of the handle (see Fig. 358), which by travelling down the spiral grooves in the spindle causes the blade to revolve. It is useful for rapidly driving a number of screws in a small space. If the blade is buried in its handle as far as may be, the tool can be used as any ordinary screwdriver for turning either forwards or backwards. A quick-action screwdriver (see Fig. 359), has a wooden handle of ordinary shape, into which slides a metal rod traversed from end to end by two spiral grooves—one right- and one left-handed—which receive an adjustable pin placed just inside the handle-sheath. A moderately strong coiled spring forces the rod outwards from the handle when not under pressure. The outer end of the rod is provided with adjustable jaws in which to hold slot bits. A turn of the ferrule at the end of the handle tightens the rod and admits of its being used as an ordinary screwdriver, while the twists necessary before the final tightening when driving in a screw or after the preliminary loosening when taking it out, are given very rapidly by Archimedean action following pressure of the handle in the direction of the tool’s length.
Fig. 357.—Plane iron Screwdriver.
Fig. 358.—Automatioc Screwdriver in use.
Fig. 359.—Millers Falls Automatic Screwdriver.
BORING TOOLS.
BRADAWLS.
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,