Woodwork Joints Part 13

An alternative method of dovetailing is that of cutting the dovetails first, as shown at Fig. 283. Four or six drawer sides are placed in the vice and the dovetails are sawn at one operation. A little lead (or bevel) from front to back is given whilst sawing, and if this method be used care must be taken to see that the parts of the drawer sides which will be on the inside of the completed drawer are towards the worker, or the lead will be given to the dovetails in the wrong direction.

[Ill.u.s.tration: Fig. 283.--Cutting several Dovetails at once.]

After sawing the dovetails in this manner the sides are placed in their respective positions on the drawer fronts or backs, and marked with a pounce-bag or by using the saw-blade method. The pins are then cut in the usual way, care being taken that the saw kerf be on the outside of the marks, otherwise the pins will finish too slack to engage with the tails.

FRAME DOVETAILS.--Fig. 284 is a sketch of a constructional frame such as is used for building up a cornice or plinth. At the joint marked A an edge barefaced dovetail is shown. From the separated sketches of the joint (B) it will be seen that the dovetail can be put together either from the top or the bottom of the framing as all its edges are parallel; glue is relied upon to hold it in position. The centre stretcher rail at Fig. 284 is similar, except that in this case it is a complete dovetail in place of a barefaced one.

[Ill.u.s.tration: Fig. 284.--Constructional Frame (as for Plinth or Cornice) showing application of the Dovetail Joint.]

Some workers, when making either of the above joints, prefer to give a slight bevel to the dovetail, so that it drives tightly into the housing when put together.

A variation of this type of dovetail is frequently used to joint internal uprights to the horizontal shelves of writing desks, cabinets, and bookcases, etc. The dovetailed portion is parallel for about three-fourths of its width; the remaining part is tapered towards the front edge and notched away at the face so as to conceal the method of construction. An ill.u.s.tration of the top portion of a division 14 ins.

wide is shown at Fig. 284, C. The other portion is of course dovetailed to fit it.

BLIND LAP-DOVETAILING.--At Fig. 285 is shown a type of blind lap-dovetailing. This makes a good, sound joint, but it has the disadvantage of showing a small portion of the timber of the front rail end-way of the grain. Joints of this kind are used for cornices, boxes, etc., and also for painted furniture.

[Ill.u.s.tration: Fig. 285.--Blind Lap-Dovetailing.]

[Ill.u.s.tration: Fig. 286.--Housed and Mitred Dovetail.]

HOUSED AND MITRED DOVETAIL.--Fig. 286 is another form of dovetail--commonly called a housed and mitred or rebated and mitred dovetail. In this instance we see that a small portion is mitred at top and bottom edges, and when used in plinth or cornice work, or for making tea-caddies, etc., the edges are (when completing the work) covered either with the moulding, which is planted on the cornice or plinth, or with the top and bottom of the box or tea-caddy.

The method of making a housed and mitred dovetail joint is seen in Fig.

286. The ends to be joined are planed up true and square and then rebated as shown. The dotted lines indicate the portion which has been worked away. The dovetails are now sawn and pared out in the usual way and the part denoted by the arrow is afterwards cut away with a chisel and finally finished to a smooth surface with a rebate plane; the method of working is shown at Fig. 287, where the dovetail pins are seen with the waste portions cut away.

[Ill.u.s.tration: Fig. 287.--Working a Housed and Mitred Dovetail Joint.]

Fig. 287 also shows the method of cutting away the mitred part. A temporary piece of wood is planed to a true mitre and placed underneath the dovetailed piece to form a template. Both pieces of the timber are now secured to the bench with a handscrew or cramp; the template A will form a guide for the chisel and rebate plane and allow a sharp edge or arris to be worked on the mitre.

A SECRET MITRED DOVETAIL joint is ill.u.s.trated at Fig. 288; it is used in all the better cla.s.s of cabinet and box work. Fig. 288 shows the pieces separated; note the mitre at the top and bottom edge.

[Ill.u.s.tration: Fig. 288.--Secret Mitre Dovetailing.]

[Ill.u.s.tration: Fig. 289.--Dovetailed Keys for Wide Surfaces.]

DOVETAIL KEYING.--Fig. 289 is a method used to prevent wide boards such as signboards, wide and shaped pediments, etc., from casting or warping.

It is called dovetail keying. Beyond calling attention to the fact that the angles at the edges of the keys, where they are bevelled, should be at or about 75 degrees, nothing further need be said, as the drawing is self-explanatory. Angle dovetail keying is shown at Figs. 290 and 291.

[Ill.u.s.tration: Fig. 290.--Dovetail Key.]

[Ill.u.s.tration: Fig. 291.--Dovetail Keying on the Angle.]

[Ill.u.s.tration: Fig. 292.--Bow-fronted Door Dovetailed Edgeways.]

OTHER VARIETIES.--At Fig. 292 we have an everyday method of jointing circular-fronted cabinet door frames. Great care must be taken in setting out and making, or a twisted frame will result.

Then at Fig. 293 are shown two familiar examples of dovetailing the bearer to the carcase end of a dressing table or washstand.

Fig. 294.--Lap-dovetailing the top of a wardrobe to the carcase end.

Other examples, such as the top of a bookcase to the sides, will suggest themselves.

Fig. 295.--Side view of a jewel drawer with a moulded drawer front as used on dressing tables, etc. This shows the necessity of bevelled dovetailing in order that the drawer front may be kept as thin and light as possible.

[Ill.u.s.tration: Fig. 293.--Carcase Work, showing Bearer Rails Dovetailed.]

Fig. 296.--Bevelled dovetailing when pins are at right angles to the end cut.

Fig. 297.--Bevelled dovetailing when the centre line of the pins is parallel to the edges of the work, used for making "hoppers," food troughs, knife boxes, etc. One corner of the box shows the joint separated.

[Ill.u.s.tration: Fig. 294.--Lap-Dovetailing.]

[Ill.u.s.tration: Fig. 295.--Jewel Drawer Side.]

[Ill.u.s.tration: Fig. 296.--Bevelled Dovetailing.]

[Ill.u.s.tration: Fig. 297.--Bevelled and Dovetailed Box, showing the Jointing of One Corner Separated.]

Fig. 298.--An example of oblique dovetailing, as used on "hoppers" when one piece is vertical and the other piece is inclined.

Fig. 299.--Method of dovetailing small boxes. The box is dovetailed in one width and the top and bottom glued on; the sides and ends are then cut along the dotted line, thus forming the lid. It will be noticed that a specially wide dovetail pin must be left so as to form part of the lid and part of the lower portion.

[Ill.u.s.tration: Fig. 298.--Oblique Dovetailing.]

[Ill.u.s.tration: Fig. 299.--Dovetailing for Small Box.]

SETTING OUT THE JOINT.--For constructing a dovetail joint at the corner of a frame, as Fig. 300, it is necessary at the outset to trim up the ends of the timber square and true. This may be accomplished by neatly sawing to the line and paring the end of the wood with a sharp chisel, or by bringing the wood to a finish with a finely-set plane, such as an iron-faced smoothing plane. The ends of the wood must be perfectly square when tested from either the face side or from the marked edge.

[Ill.u.s.tration: Fig. 300.--Corner Dovetail.]

[Ill.u.s.tration: Fig. 301.--Squaring.]

Take a cutting gauge and set it to equal the thickness of the timber, and, holding it as already shown at Fig. 273, strike the gauge lines on the wood as ill.u.s.trated at Fig. 302, G. Proceed to mark out the dovetail pins, as at Fig. 303; in this ill.u.s.tration G again shows the gauge line.

The inclination of the lines across the end of the wood should not be too great, or the joint will be a weak one, and the edges of the dovetails will be liable to crumble away when the work is knocked together.

DOVETAILING TEMPLATE.--Many workers who are constantly engaged upon dovetail joints make a small wooden template, as shown at Fig. 304. This template is generally of hardwood, such as beech or walnut. The method of obtaining the correct angles of such a template has already been given on p. 134. Notice that the lines _bb_ (Fig. 303) of the dovetail pins do _not_ bevel; they are parallel to the sides of the wood and at right angles to the end of the wood as shown.

[Ill.u.s.tration: Fig. 302.--Gauging.]

[Ill.u.s.tration: Fig. 303.--Marking the Pins.]

CHISEL WORK.--After marking out, as shown at Fig. 303, place the wood on the bench and proceed to chop away the centre portion in the following manner. Hold the chisel on the bevel and cut out a small piece to form a channel at the gauge line. Now hold the chisel in a vertical position, and with a mallet strike it so as to make a cut about 1/8 in. deep. Then hold the chisel on the bevel again and cut away more waste wood; proceed alternately, first forcing the chisel down vertically, and then paring the wood away with the chisel held obliquely, until you have cut half-way through the thickness of the wood.

[Ill.u.s.tration: Fig. 304.--Hand-made Template for Marking Dovetails.]

[Ill.u.s.tration: Fig. 305.--Testing.]

[Ill.u.s.tration: Fig. 306.--The Marked Piece.]

Turn the wood over and repeat the various operations until the core, or waste piece, is removed. Pare away any little irregularities which may be left in the corners with an 1/8-in. chisel, thus leaving all smooth and neat. Lay the piece of wood which is to have the dovetail marked on it flat upon the bench, and take the piece with the dovetail pins cut upon it and place in the position shown at Fig. 305.