Woodwork Joints | Page 4

raw material.

The method of using iron dogs is illustrated in Fig. 25, and it will be
observed that owing to the wedge-like formation of each fang (see
enlarged sketch) the dog exerts the necessary pressure to close the joint.
At the centre of this illustration is suggested the home-made hardwood
blocks, baseboard and wedges referred to on page 4.
Fig. 27 shows how the iron sash cramps are used to apply pressure to
the joint. As this method is in some cases apt to bend and distort thin
boards it is wise practice to fix (as a temporary measure) a stout piece
of straight wood on to the board to be joined by using two handscrews
as shown at the left hand of the illustration. At the right hand of the
sketch a wooden cramping arrangement of the box type is given, and by
wedging up the boards are closed together. It is obvious that if this type
of box cramp be used it will prevent the boards buckling and the
handscrew method at the left may be dispensed with.

THE HALVED JOINT
The halved joint is frequently known as half-lapping, and sometimes as
checking and half-checking. In the majority of cases it is made by
halving the two pieces, i.e., by cutting half the depth of the wood away.
There are, however, exceptions to this rule, as in the case of
"three-piece halving" (or, as it is sometimes called, "third lapping") and
in the halving of timber with rebated or moulded edges. Halving is one
of the simplest methods of connecting two pieces of timber, especially
where it is desired to make frames and bracket supports for either
inside or outside use.
[Illustration: Fig. 28.--Frame, with various halved joints. These joints,
numbered 1, 2, 3, etc., are shown in detail in Figs. 29 to 38.]
Fig. 28 shows the elevation of an imaginary frame which is indicated as
made up of a number of halving joints; it shows also the application of
the various joints to this class of work. Each joint used in the
construction of this frame may be dealt with separately. The numbers
marked on Fig. 28 refer to the individual joints, shown separately in

Figs. 29 to 38.
[Illustration: Fig. 29.--Halved Corner Joint.]
[Illustration: Fig. 30.--Halved T Joint.]
Fig. 29 shows the "Halved Joint" at the corner of the frame where the
two pieces form a right angle (see Fig. 28, 1). Each piece is halved and
shouldered at opposite sides, thus forming a perfect fit one with the
other and giving a strong joint with a minimum amount of labour. For
inside work the joint would be glued and screwed together, the screw
heads being countersunk so as not to come in contact with the cutting
iron of the plane when levelling off the work. For outside work, in
exposed positions where the work will have to withstand the weather,
the alternative method of smearing the joint with paint or with a
mixture of varnish and white lead would be advisable, the joint being
nailed or screwed. Fig. 29 shows the two pieces separated.
Fig. 30 shows a similar joint to the above, but in this case the top rail
runs through and it is generally spoken of as a "Halved T Joint" (Fig.
28, 2). It may be used in nearly all cases where a top or bottom rail runs
through an upright. The method of securing the joint is as before. Fig.
30 shows a sketch of the joint separated.
[Illustration: Fig. 31.--Oblique Halving with Shoulder.]
[Illustration: Fig. 32.--Oblique Halving.]
At Fig. 31 is shown an "Oblique Halving Joint," where the oblique
piece, or strut, does not run through (Fig. 28, 3). This type of joint is
used for strengthening framings and shelf brackets; an example of the
latter is shown at Fig. 48. A strut or rail of this type prevents movement
or distortion to a frame diagonally (generally spoken of in the trade as
"racking"). Fig. 31 shows the joint apart.
Fig. 32 is an example of Oblique Halving with the upper piece running
through (Fig. 28, 4). This joint is used in similar positions to Fig. 31,
and has in some cases the disadvantage of showing end grain at the top

of the frame. The sketch shows the two pieces separated.
Fig. 33 is "Dovetail Halving," the dovetail running through the top
piece (Fig. 28, 5). This is a strong joint, used where outside strain is
likely to occur in the top piece, the dovetail preventing the rail from
being drawn away from the shoulder. The two pieces are shown
separate.
[Illustration: Fig. 33.--Dovetail Halving.]
[Illustration: Fig. 34.--Mitre Halving.]
At Fig. 34 is seen "Mitred Halving," a somewhat weak joint, but
necessary in mirror frames, etc., where good appearance is