h the stile and make the tenon to
match it; the edge of the finished work does not then show any indication
of the joint, and it leaves a nice clean surface at the edge of the work
for polishing or varnishing.

[Illustration: Fig. 189.--Interlocking Joint for Seat Rails of Chair to
Leg.]

INTERLOCKING CHAIR JOINT.--A joint designed with a view to strengthening
the construction of chairs at the point where they are weakest is shown
in Fig. 189. The joint is an interlocking one so arranged that, once the
chair is glued up, no motion of the side rail can be possible. The groove
in the side rail tenon is cut in such a manner that, on the insertion of
the back rail tenon, the joint actually draws up and, having done so, is
locked in position. The exact location of this groove is obtained in a
similar manner to that used in marking out tenons for drawbore pinning,
_i.e._, the tenon is inserted in its mortise and the position of the back
rail mortise transferred to it, after which the lines are set back by
1/64 in. (approximately) to cause the joint to draw.

From the illustration the construction of the joint should be clear. The
method is particularly adapted to a section of rectangular form where one
side is longer than the other, such as the back leg of a chair, as this
shape allows for the accommodation of the extra length of tenon
required.

THE DOWELLING JOINT

Dowelling is the term generally given to the method of jointing timber
and other materials by wooden or metal pegs, which are called dowels. For
cabinet-making and similar work straight-grained beechwood dowels are
mostly used; these may be bought by the gross, in lengths of about 36
ins., and of any desired diameter.

[Illustration: Fig. 190.--Steel Dowel Plate.]

MAKING DOWELS.--Many, however, prefer to make what they require for the
work in hand, and the following is the method that is generally employed.
Pieces of straight-grained wood are wrought to a square section, after
which the corners are planed away to form an octagonal section. The sharp
corners are now planed away, and the roughly formed dowel is driven
through a steel dowel plate, Fig. 190, by the aid of a heavy hammer, thus
giving the necessary roundness and finish to the dowels. When hammering
dowels through a plate the hammer should on no account be allowed to come
in contact with the face of the dowel plate, or the cutting edge of the
hole will be spoilt. Simply drive the dowel