Drawing Board and T-Square

DRAWING BOARD AND T-SQUARE Every man and boy who is interested in woodwork ought to own and be able to use a set of drawing instruments. So important is it for one to know exactly what he is going to do, before he undertakes a piece of woodwork, that many manual-training teachers will not allow a student to begin a piece of any importance until he has first made a drawing, showing all the parts, with their dimensions, and the man ner of assembling or putting them together.

True, many good carpenters and cabinet makers never make drawings, but simply work out their ideas as the work progresses. This method of working, however, has limitations. It means that the one having the idea must work out that idea. If he should wish to have another do so, or if he should wish the help of another, he must make drawings.

The amateur usually has not the ability to foresee the difficulties of construction which will arise, as has the experienced workman; hence the planning necessary to make the draw ing will insure his avoiding many mistakes by becoming thoroughly acquainted with his work before he begins it.

The necessary instruments for ordinary work are few in number, and can, for the most part, be made by the craftsman himself.

The drawing board (Fig. 27) should be con structed of the softest material. Soft or white pine is probably the easiest to secure, and is most commonly used. The stock must be soft, else the thumb-tacks which are used to fasten the paper to the board cannot be easily placed and removed.

Cut roughly two or more boards, which can be squared up to five-eighths by eighteen by twenty-four inches after they have been jointed together. Square the edges, using try-square and'straight-edge for testing. The edges should be so planed that when two adjoining edges are placed together they shall fit at all points. Glue the edges, and clamp the pieces together by means of cabinet-maker's clamps. Use hand clamps also, if necessary, to keep the boards from buckling.

While the glue is drying, prepare two cleats by squaring up two pieces to five-eighths by two by seventeen inches. They may be beveled, as shown in Fig. 27. Drill and countersink holes in them for a sufficient number of screws to fasten the pieces together firmly.

After the glue has hardened, scrape off the surplus, and plane up the two broad surfaces smooth and level. Square up the edges and ends. The ends must be absolutely straight and square, as the head of the T-square will usually be placed against them.

Next fasten the cleats near the ends of what is to become the under side of the board. The construction shown in Fig. 27 is probably not the best, but it will be found difficult enough. Those who can do so are advised to put the cleats on the ends of the board, instead of under neath. This can be done by matching the cleats to the ends of the board. Use a matching plane

to put tongues on the ends of the board, and also, after changing the bit, to put the corre sponding grooves in the cleats. Fig. 28 shows this joint.

If the board is to be of the approximate size of the one just described, the ten-inch boards should be cut so as to square to five-eighths by eighteen by twenty and three-fourths inches. This allows three-eighths of an inch for the length of each tongue.

The cleats should be cut roughly a little longer than eighteen inches, so as to allow for cutting off after they have been fastened in place.

Glue the tongues, put on the cleats, and clamp the whole together. Sometimes a screw is placed through the cleat at its middle, and then into the board.

There are several advantages in this con struction over the first described. The cleats are less in the way. When the cleats are screwed across the grain of the wood, the shrinkage of a board as wide as this might cause it to crack or open at the glue joint. Or the swelling of the board might cause its surface to become curved. With the second type of fastening, the board may move in the grooves of the cleats without hindrance, unless too much glue has been used.

Allowance for the "give and take" of a board which has cleats fastened to it, is often made by making the screw-holes larger than is necessary for the screw itself. Roundhead screws with washers are then used, the washers covering the holes.

The T-square (Fig. 29) should be made of a harder wood than that of which the drawing board was made. Pear wood makes a service able instrument. Any wood that will not mar readily nor warp easily, will do.

Sometimes several kinds of wood are glued together so that the warping of one may be counteracted by that of the other. Again, T squares often have their edges made of some transparent substance such as celluloid, so that the markings on the paper can be seen through them. The advantage is obvious. The one piece T-square, however, will answer all neces sary purposes.

For the head, square up a piece of stock to three-eighths by two by eight inches. The outer corners are to be rounded, using a one half-inch radius. The inside edge, or the edge which is to rest against the board, must be per fectly straight and square.

The blade of the T-square should be squared up to one-eighth by two by twenty-four and one half inches. The edges, especially the upper edge, should be perfectly straight and square.

Fasten the blade to the head, using five small screws as shown in Fig. 29. Use the steel square to get the edges of the blade at right angles to the inside edge of the beam. A one-quarter inch hole in the blade near the end will form a convenient place by which to hang the instru ment upon a nail when it is not in use.