INTRODUCTION

In woodworking joinery and other related crafts such
as furniture/cabinetmaking and shop- fitting, there
are basically three applications of jointing timber
that concern the craftsperson. 1) Frame joints, where
pieces of timber are joined together in various ways,
at right- or oblique- angles to each other (as in a door
with stiles and cross rails – or a drawer with front,
back and sides); 2) Edge joints, where pieces of timber
are joined together side- by- side, with their fibres
parallel to each other (as in the widening of a shelf or
a tapered stair- tread); and 3) End joints, where pieces
of timber, with the ends of their fibres butting up to
each other, are joined together (as in the lengthening
of a counter- or pub bar- top, or as in modern so-
called ‘gluelam’ work).

FRAME JOINTS

Mortise and tenon joints

Figure 3.1: This traditional frame- jointing method,
which has stood the test of centuries, is still widely
used in the manufacture of good- quality joinery. It has
not really been satisfactorily superseded by anything
more modern; although it has been challenged – more
successfully in mass- produced furniture- making, than
purpose- made joinery – by dowelled joints; and comb
joints using improved adhesives and gluing tech-
niques.
Possibly, one of the least- recognized features of
the most common type of mortise and tenon joint
(the wedged, through- tenon; illustrated in Figure
3.1), is that when the wedges are glued and driven
in to the mortise on each side- edge of the tenon,
the tenon (with the wedges glued to it) effectively
takes on the shape and locking- action of a dovetail

• that cannot easily be pulled apart. Also, because
  the tenon’s fibres have been forced into a state of

compression by the side- pressure from the driven-

wedges, any eventual shrinkage in the tenon’s width

will not result in lessening the holding- power

of the joint. However – unlike the blunt- ended

wedges illustrated below – wedges are often cut to

a sharp, pointed shape, this being a deviation from

the traditional wedge-shape, which was made to

have a blunted point of between 2 to 4mm. The

valid reason for giving the thin end of wedges this

thickness was to create a state of compression deep

down, near the shoulders of the tenon, as well as

in the obvious upper areas where the wedges are

driven in.

3

Joinery joints

Their proportions and applications

Blunt-ended wedges

Rail

Shoulder

each side

Through-tenon

cheek each side

Dovetail-shaped mortise

Stile

Figure 3.1 Separated view of mortise and tenon joint to

plain- edged timber.

Shoulder variations

Figure 3.2(a)(b)(c)(d): As illustrated below, tenons

mortised into plain- edged timber can have from one

to four shoulders with which to form an abutment up

against the surface of the mortised edge. And those

that have none, like the ends of wooden louvres, verti-

cal slats in a cot or garden seat, are not really tenons;

they are housing joints.