Part 14 (1/2)

SAW WORK.--Take a marking awl, or a knitting needle which has had its end sharpened, and mark the lines of the dovetail in a similar manner to that shown at Fig. 307. Remove the piece A, Fig. 305, and the lower piece shown at Fig. 305 will clearly show the marks _aa_ as they appear in Fig.

306. Place the piece (Fig. 306) in the vice, and saw _outside_ the lines AA, as shown in Fig. 308.

[Ill.u.s.tration: Fig. 307.--Marking Dovetails with Marking Awl.]

After sawing down the lines AA, Fig. 308, place the wood in the vice and, guiding the saw blade with the index finger of the left hand, cut away the small piece at the side (see Fig. 275). Repeat the operation as may be necessary, and the completed joint will be similar to that shown at Fig. 300. If the sawing is not neatly done it may be found necessary to pare the shoulder with a sharp chisel.

DRAWERS.--When dovetailing drawers or boxes it is necessary to square up the ends of all the stock and gauge them, as shown at Fig. 273. This ill.u.s.tration shows how to gauge the lines on a drawer side; the dovetailed joint in this case, however, does not run through the drawer front and leave the work unsightly, as the joint at Fig. 300 would do.

The method used is shown at Fig. 309, and it is commonly known as lap-dovetailing. Most workers cut the dovetail pins on the drawer fronts and the drawer backs first, after which they mark the drawer sides with the marking awl. The dovetailing of the drawer back is shown at Fig. 310.

This is the type known as ”through dovetailing,” the method being similar in regard to tool operations as the single joint shown at Fig. 300.

[Ill.u.s.tration: Fig. 308.--Sawing the Dovetails.]

[Ill.u.s.tration: Fig. 309.--Lap-dovetailing Drawer Front to Drawer Side.]

[Ill.u.s.tration: Fig. 310.--Through Dovetailing.]

[Ill.u.s.tration: Fig. 311.--Chipping Waste of Lap Dovetail.]

When the pins on the drawer front have been sawn, the waste material is cut away, as at Fig. 311. First stab down with the vertical chisel, which must make the cut about 1/32 in. in front of the gauge line (see ill.u.s.tration). This commencing of the cut slightly in front of the gauge line is a very important feature. The chisel may be likened to a wedge, and if the chisel edge be placed exactly upon the gauge line and force be applied to the handle, it will force the timber away equally on each side of the gauge line, and the finished depth of the hole will therefore be too deep for the thickness of the drawer side; in other words, it will press itself over the gauge line on both sides.

By taking the first vertical cut on the waste side of the gauge line, and then removing a small piece with the chisel held obliquely, as at Fig.

311, the wood is removed and less resistance is offered to the chisel when the next vertical cut is made. This overshooting the gauge line is a common fault with the beginner, who is puzzled at the result because he is certain he had his chisel exactly on the gauge line when he commenced his vertical cut. It is especially noticeable in soft-grained woods.

To cut away the waste of a lap-dovetail (Fig. 311), the vertical and oblique cuts are repeated until the final tr.i.m.m.i.n.g up is required, and now is the time to finish both the vertical and the horizontal cuts exactly on the gauge lines.

Some workers prefer to cut the drawer sides first, and if this method is preferred (and it has its advantages for cheap work) several drawer sides are cut at once by placing four or six behind one another in the vice and sawing them all at one operation.

The drawer front is placed in the vice, and the drawer side held upon it, whilst the saw blade is placed in the saw kerf and drawn smartly forward.

This will give the required marks at the exact position desired. It must be remembered, however, to saw just inside these dovetail-pin lines, otherwise the finished joint will be too slack, owing to the removal of the sawdust, which is practically equal to the thickness of the saw blade.

MACHINE-MADE DOVETAILS.--As a general rule machine-made drawer and box dovetails show both the pins and the tails of exactly the same size. The reason is obvious after an inspection of Fig. 314, which shows the position in which the pieces are held during the machining operations. In spite of a certain amount of prejudice they are satisfactory and thoroughly reliable and have their place in modern shop and office fittings.

[Ill.u.s.tration: Fig. 312.--Machine-made Drawer Front and Side, Apart.]

[Ill.u.s.tration: Fig. 313.--The Parts Together.]

[Ill.u.s.tration: Fig. 314.--Position when Machined.]

DOVETAIL GROOVING

The dovetail housing joint should first be carefully marked out with a marking knife, so as to cut across the fibres of the wood. For obtaining the bevel on the edge of the wood a joiner's bevel may be used, and the angle should not be too acute. (See previous chapter.) Take a chisel and pare away a small channel as at A, Fig. 315, to form a small shoulder to guide the saw.

[Ill.u.s.tration: Fig. 315.--Paring away Channel for Dovetail Grooving.]

With a fine tenon or dovetail saw, cut the saw kerf as at Fig. 316. If any difficulty is experienced in cutting the kerf true and square, you may resort to the method shown at C, Fig. 315; a small temporary piece of timber has been screwed on the top of the work to form a guide for the saw.