Fig. 2324.
In [Fig. 2323] is an example in which the forms of both sides of a piece require to be exactly alike, and the easiest method of accomplishing this is as follows:—The face a should first be made true, and face b made parallel to a. A centre line c may then be drawn, and from it the lines e, e may be marked. The lines d are then drawn parallel to a a, lines e being made square to d and to a. The sides e may be calipered to width and parallelism, and all that will then remain is to file the angles f, f and the ends g, g to their required lengths. For f, f all that is necessary is a template formed as in [Fig. 2324]. The object of dressing the ends g, g last is that if they were finished before, their faces e would have to be made at exactly correct distances from them, which would render the job considerably more difficult.
Fig. 2325.
Fig. 2326.
[Fig. 2325] represents a sketch for a piece of work whose two sides are to be shaped exactly alike, requiring a template of the form of the work, as shown. From this a second template, [Fig. 2326], is made, and to this latter the work may be filed. To make the template in [Fig. 2325], which represents the work, the edge x x must be made straight, and the edge d parallel to it at the proper height. A centre line s is then marked, and the edges at e may be filed equidistant from s and square to d; hence they will be parallel to each other. The side sections f should then be filed equidistant from s and parallel to each other. They should be the proper width apart and square to d, being tested in each of these respects. The line joining e and f should be left full, as denoted by the dotted line at a on the right. The edges at c, c should then be filed, calipering them from the edge x x. Edges g, g are obviously equidistant from s and parallel to s, or, what is the same thing, at a right angle to x x, from which they may therefore be tested with a square, and, finally, the edges b are made parallel to x x, and the ends h made square to x and equidistant from s. We have now to file the angular groove at a, and to get this true after marking its depth from the lines at a, we file it first to the lines as near as may be by the eye and very nearly to the full depth. We then make a small supplemental male template t, [Fig. 2327], equal in width to the distance e f, or, in other words, to the width of the step at a, and having its edges quite parallel. Its end is then filed to fit the groove at a, when its edge meets and coincides with edge e, as in [Fig. 2327], t representing the supplemental template. It is clear that when the V-groove a is so filed that t will fit it with either of its edges against e, the angles of the groove will be alike, and we may then make a male gauge, as in [Fig. 2326], that may be used to mark or line out the work and to use as a template to file it to, its edge h being kept parallel to face d, [Fig. 2325], of the work.