Chapter 7 of 10 · 3974 words · ~20 min read

Part 7

Other workers prefer a pounce-bag instead of a saw. A pounce-bag consists of a piece of fairly open woven muslin filled with a mixture of French chalk and finely-powdered whiting; the muslin is tied up with a piece of thin twine like the mouth of a flour sack. All that is necessary is to place the timber in position and bang the bag on the top of the saw-cuts, when sufficient powder will pass through the bag and down the saw kerf to mark the exact positions of the lines.

SAWING THE DOVETAILS.--After marking out the pins on the drawer sides, we proceed with the next operation, that is, sawing the dovetails ready for chopping out the waste material. The drawer side is taken and firmly secured in the bench screw and sawn as at Fig. 281; it is most important that the saw kerf is kept _inside_ the line which has been scratched by the marking awl. See Fig. 280, where the dotted line represents the gauge line and the outside lines indicate the scores of the marking awl. Failure to observe this condition will result in faulty dovetailing, and it will also prove the necessity for using a finely-toothed and thin-bladed dovetail saw.

To cut out the waste wood (or core), the usual procedure is to saw away the half-dovetails as at Fig. 275. With care, this can be accomplished with the dovetail saw, thus avoiding unnecessary labour and the use of the paring chisel.

After sawing, the drawer side is placed flat upon the bench, one end in contact with the bench to prevent the drawer side from slipping away; a chisel (preferably bevelled edged) of suitable width is now taken and a small channel is cut as at A, Fig. 282. The method of cutting this channel is shown in the same illustration. The chisel-cut is started about 1/8 in. from the gauge line; the cut is made right up to the gauge line, which (when gauging) was made 1/32 in. deep so as to cut the cross fibres of the timber. A small piece of waste wood will therefore come away as at A.

The object of cutting this small channel is so that, when the chisel is held vertically on the gauge line and struck with the mallet, the chisel will have no tendency to force its way backward and overshoot the gauge line. The waste or core is now removed by holding the chisel approximately vertical and applying sufficient power to drive it half-way through the timber. The drawer side is now turned over, the operation repeated, and the core pushed out. Care must be exercised whilst cutting away the core to ensure the chisel being held nearly perpendicular; if too much lead (or bevel) be given, a faulty and undercut dovetail will be the result. Undercut dovetails prevent a proper grip of the glue; they give a weak joint, and often cause the face of the drawer side to be splintered whilst driving up the joint. If it be necessary to ease one or two shavings from off the drawer side whilst fitting the completed drawer in the carcase, the joint will show a greater gap as each succeeding shaving is removed.

In common work, especially in soft timbers, many workers allow the pins of a drawer back to run through the sides about 1/16 in. and hammer down the pins of the dovetail. This is called "bishoping the dovetails," and is unnecessary if the work be properly made and fitted.

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.

[Illustration: 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.

[Illustration: 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 illustration 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.

[Illustration: Fig. 285.--Blind Lap-Dovetailing.]

[Illustration: 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.

[Illustration: 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 illustrated at Fig. 288; it is used in all the better class of cabinet and box work. Fig. 288 shows the pieces separated; note the mitre at the top and bottom edge.

[Illustration: Fig. 288.--Secret Mitre Dovetailing.]

[Illustration: 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.

[Illustration: Fig. 290.--Dovetail Key.]

[Illustration: Fig. 291.--Dovetail Keying on the Angle.]

[Illustration: 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.

[Illustration: 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.

[Illustration: Fig. 294.--Lap-Dovetailing.]

[Illustration: Fig. 295.--Jewel Drawer Side.]

[Illustration: Fig. 296.--Bevelled Dovetailing.]

[Illustration: 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.

[Illustration: Fig. 298.--Oblique Dovetailing.]

[Illustration: 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.

[Illustration: Fig. 300.--Corner Dovetail.]

[Illustration: 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 illustrated at Fig. 302, G. Proceed to mark out the dovetail pins, as at Fig. 303; in this illustration 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.

[Illustration: Fig. 302.--Gauging.]

[Illustration: 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.

[Illustration: Fig. 304.--Hand-made Template for Marking Dovetails.]

[Illustration: Fig. 305.--Testing.]

[Illustration: 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.

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.

[Illustration: 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 illustration 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.

[Illustration: Fig. 308.--Sawing the Dovetails.]

[Illustration: Fig. 309.--Lap-dovetailing Drawer Front to Drawer Side.]

[Illustration: Fig. 310.--Through Dovetailing.]

[Illustration: 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 illustration). 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 trimming 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.

[Illustration: Fig. 312.--Machine-made Drawer Front and Side, Apart.]

[Illustration: Fig. 313.--The Parts Together.]

[Illustration: 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.

[Illustration: 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.

[Illustration: Fig. 316.--Cutting the Saw Kerf.]

[Illustration: Fig. 317.--Old Woman's Tooth Plane.]

[Illustration: Fig. 318.--Guide Block for Bevelling.]

Fig. 315, B, shows the small channel formed by the chisel prior to the sawing operation. The sawing of the bevelled side is worked in a similar manner; but occasionally we find amateurs who adopt the method shown at Fig. 318. A block of wood (H) is first made by boring a 1-1/4-in. hole through its entire length, and afterwards making a saw cut at the desired bevel. The object of this block, which is kept specially for the purpose, is to form a guide for those who have not full control of the dovetail saw; the back of the saw clears the hole, and the required bevel is obtained. When a saw cut has been made at each side of the groove, the surplus timber is pared away in the following manner: Cut away portion E, Fig. 319; then cut away portion F, and lastly cut away the apex portion marked G. Continue by this method of paring until the approximate depth is reached. To ensure a correct depth throughout the entire groove, the router plane (or, as it is often called, "the old woman's tooth plane," Fig. 317) is used.

[Illustration: Fig. 319.--Showing Method of Paring.]

[Illustration: Fig. 320.--Channelling the Alternate Piece.]

With regard to cutting the alternate piece, it is necessary to first plane the end of the shelf true and square. With a cutting gauge strike the line K, Fig. 320; the required bevel on the edge (J) is then set out, and with the chisel a small channel is again formed. With the tenon or dovetail saw cut down the line K to the required depth, and carefully pare away the wood with a sharp chisel to the correct shape.

THE MITRED JOINT

Although mitreing is used in everyday woodwork, it comes last in our list of regular joints simply because it has been partly dealt with in almost every previous chapter. For example, we have mitre halving in Fig. 34, a mitre bridle joint in Fig. 74, a tongued and grooved mitre in Fig. 116, mitred mortise and tenon joints in Figs. 148 and 159, a dowelled mitre frame in Fig. 202, and a mitred dovetail in Fig. 286.

[Illustration: Fig. 321.--Mitred Skirting.]

[Illustration: Fig. 322.--Curved Mitre.]

[Illustration: Fig. 323.--Halving the Angle.]

MITREING.--The term mitreing is generally used to denote the type of joint used at the corner of a picture frame; or where two pieces of wood are bevelled away so as to fit each other, as the skirting or plinth mould at Fig. 321. In these cases the timber is cut so that the joint is at 45 degrees to the face, and the two pieces, when placed together, form an angle of 90 degrees (a right angle).

The term mitreing, however, is not confined to the fitting of timber around a right angle; it may be justly applied to the fitting of a moulding around an angle irrespective of the number of its degrees.

One often hears such terms as "a half mitre," used to denote the fitting of a moulding around an octagonal column or pedestal, and probably it would be more correct to describe the joint as a mitre cut at 22-1/2 degrees. Mitreing consists of halving the angle and making each piece to fit the line of bisection. Should the angle be bounded by straight lines, as at Fig. 321, then the mitred joint will be a straight line, but should the angle be bounded by a curved and a straight line, as at Fig. 322, A, or by two curved lines, then the mitred joint will have to be a curved line if the mouldings are to be of the same section.

[Illustration: Fig. 324.--Sawing Block for Mitreing.]

FINDING THE ANGLE.--For straight mitres, the mitre joint line is found by bisecting the angle, as shown in the various examples, and the following instructions are given to enable the reader to follow the diagram (Fig. 323). Take a pair of compasses, or dividers, and with any convenient opening strike out the arc A, B. Put the point of the compasses on A, and mark another arc C; then, without altering the distance between the points of the compass, put the point on B, and mark the arc D. Draw the line E from the corner, so that it cuts through the intersection made by the arcs C and D. The angle A B is now halved by the line E, and this method may be applied to any angle.