Fig. 2426.
Fitting Brasses to Boxes or to Pillar Blocks.—In the operation of fitting brasses to their boxes or to pillar blocks there are two things to be especially guarded against: First, having the brass let down one-sided, as shown in [Fig. 2422]; and next, aslant, as shown in [Fig. 2423]. The first depends on taking the proper amount off the two side faces, and the second in cutting the inside of the flanges fair. To cut the side faces fair, grip the brass in the vice, as shown in [Fig. 2424] (the brass being shown in section), in which a is a block of wood. Take the measure of the box, down where the brass will come when home, and, if there be any taper to the box, set the inside calipers to the top of the location for the brass, and after the brass is in the vice place a square under one side-face, as at b in [Fig. 2426], and see how much there is to come off. This saves the use of outside calipers, and is better because, not only is the trouble of setting the latter avoided, but the inside calipers can be tried to the box and the work in an instant, and a correction can at once be made if the calipers have got shifted. The cape chisel, or cross-cut, as it is sometimes termed, should first be used, taking a cut close to the flange, and making it half as deep as the calipers (applied as shown in [Fig. 2426]) show there is metal to come off. Then a similar cut should be taken close to the other flange, especial care being taken to take both cuts equally deep, and leaving as much to come off the other side face of the brass; otherwise, the brass will come atwist. Then take a straight-edge, and, placing its edge fair with the two chisel-grooves, while holding it firmly against the joint face of the brass, mark a line running from one chisel groove to the other; this line serving as a guide for the depth of all the other cape-chisel grooves. Now cut off the intermediate spaces with the flat chisel, using a straight-edge as a guide. If the box is taper, chip the side face to a corresponding taper, using a bevel-square, or estimating the amount by the eye if it is not too much. Now file the chipped surface flat and true, and then turn the brass upside down, gripping it with the wood as before, and dress the other side face (applying the inside calipers as in [Fig. 2426]), and bring that face down to within about 1⁄64 inch of the size to which the calipers are set. If the block of wood is made a little shorter than the length of the brass, the calipers can be applied without moving the brass from or in the vice. The method of applying the square to these side faces is shown in [Fig. 2425], in which a is the brass in section, b a straight-edge, and c a square.
Fig. 2427.
Fig. 2428.