Series editors' preface - Wood Tools

unwanted movement in the joint is restricted.
Deviation from this ideal may result in loads
being unevenly distributed, stress concentrations
arising, or movement that will lead to the
destruction of glue lines, bearing surfaces and
failure of the joint and the structure of which
it is a part.
There are so many possible combinations of
the above factors that may arise in different
joints that only a few can be selected for further
discussion.
2.7.3 Dovetail joints
The dovetail (Figure 2.24) is the strongest joint
for joining pieces of wood together at rightangles
in their thickness (side-grain to endgrain)
and is widely used at corners for box,
drawer and carcase construction. It consists of
interlocking tails and pins that resist tension
along the tail member but not along the pin
member. In drawers, the joint is therefore oriented
with the pins in the front and back of the
drawer and the tails in the sides while in carcases
the tails should be in the top to prevent
the sides from moving outwards. The joint
relies on the wedging action of pins and tails
to hold it together in tension and on glue
between side-grain to side-grain mating faces
of tails and pins to hold it together. Therefore,
the factors that affect both the strength and
appearance of the joint are the number and
size of the tails and pins and their slope.
Provided that an adequate amount of wood
remains across the narrow part of the tail,
increasing the number of tails will increase the
strength of the joint by providing an increased
side-grain to side-grain gluing area. It is common
to make the tails at their widest part about
twice that of the pins but for the strongest
work they can be equal. The slope or rake of
the tails is a compromise, if it is too small the
wedging-locking action will be lost but if too
Figure 2.24 Examples of angle joints: dovetail joints:
(a) through dovetail; (b) lapped dovetail; (c) double
lapped dovetail; (d) secret mitred dovetail. Joints used
in carcases: (e) cross rails dovetailed into solid side;
(f ) cross rails dovetailed into framed side; (g) top
dovetailed to side; (h) top dowelled to side; (i) top
rebated; (j) housing; (k) tapered dovetail housing
(c)
(j)
(k)
(a)
(g)
(e)
Wood and wooden structures 91
(d)
(i)
(b)
(f)
(h)