n the method of jointing framing
having semicircular or segmental heads. The left-hand diagram indicates
the method of wedging the joint so as to draw up the shoulders; the
right-hand view shows the tongueing of the shoulders, which is necessary
if thick timber has to be wrought. The sketch depicts the stile when
taken apart from the shaped head of the frame.

CLAMPING.--Fig. 172 shows the method of tenoning drawing boards, desk
tops and secretaire falls. This is commonly called clamping. The method
is used to prevent wide surfaces from winding. A variation of the joint
is shown at the left-hand side, the corners in this example not being
mitred. Fig. 173 shows the tenoning of a wide to a narrow rail when the
joint is at an angle.

INSERTED TENONS (Fig. 174).--Where two pieces of timber run together at
an acute angle it becomes necessary to use inserted tenons. Both pieces
of the timber are mortised and the inserted tenons are secured into the
widest piece. On the left is shown the inserted tenon, secured by the
method known as fox-wedging; on the right the inserted tenon has been let
into the wide rail from the edge. The narrow rail is secured by wedging
the tenons from the outside edge in the ordinary manner.

[Illustration: Fig. 170.--Open-Slot Mortise at 60 degrees.]

[Illustration: Fig. 171.--Hammer-Head Tenon Joint.]

DREADNOUGHT FILE.--At Fig. 175 is a sketch of a portion of a dreadnought
file. This has superseded the old-fashioned home-made float used to clean
out the sides of a mortise.

[Illustration: Fig. 172.--Clamping.]

[Illustration: Fig. 173.--Tenoning Narrow Rail.]

[Illustration: Fig. 174.--Inserted Tenons.]

[Illustration: Fig. 175.--Dreadnought File.]

[Illustration: Fig. 176.--External and Internal Joints.]

[Illustration: Fig. 177.--Setting out Stiles and Rails for Tenoning.]

GENERAL RULE.--In practically all cases where a single tenon is used the
thickness of the tenon should be one-third the thickness of the timber.
This leaves the timber at each side of the mortise the same strength as
the tenon.

Mortise and tenon joints for inside work may be united with glue. If,
however, the work has to stand the weather a better method is to unite
the joint with white lead, which is run down to the required consistency
with good outside varnish.

SETTING OUT THE JOINT.--The principal use of the mortise and tenon joint
is in the construction of various types of framing, such as door and
win