30 Joinery joints
practise to keep a fraction away (0.5 to 1mm) from the
knifed shoulder and then this can be more precisely
finished by vertical paring with a wide, sharp bevel-
edged paring chisel.
On certain softwood jobs, where the shoulders
are marked out by pencil, paring can be avoided if
a good degree of tenon- saw skill has been acquired
and the shoulders can be carefully finished with
the tenon saw. However, if your skill is not yet
developed and you need a shoulder to lean against,
a small v- shaped furrow can be formed to hold
the tenon saw against the shoulder. The v- shape is
started with a marking knife by simply knifing a
deep shoulder line vertically against a try square,
then by paring the waste- side of the knife- cut across
the rail (from each side) with a very sharp paring
chisel tilted to about 30°, as illustrated in Figure 3.18.
Producing wedges
Figure 3.19: Once the basic tenons have been
formed, the reduction for the haunch-allowance
can be marked onto the tenons’ cheeks. Then
each rail is placed upright in the vice and two or
more wedges – the angles of which are usually
guessed at by experienced woodworkers – are cut
from the waste area before the exact width of the
tenon is cut and the haunch projection formed by a
tenon- saw cut across the grain. However, whether
guessing or marking out the wedges as illustrated in
Figure 3.19, the wedge- angle should be about 85° (1
in 12).
This traditional technique produces wedges quickly
from waste material of the correct tenon- thickness
and eliminates what- can- be a fiddly job on separate,
short pieces of wood.
Machined and part- machined tenons
When the machine is set up accurately, precise tenons
with well- cut shoulders can be produced on heavy,
fixed single- or double- ended tenoning machines. With
such machines the usual practise is to mortise the
stiles first. This enables a short- stub (about 6mm)
trial- run- tenon to be machined on a rail- end for
trying into a mortise to check for fit and flushness.
Note that only the end grain at one end of the trial
rail needs to be marked with the mortise- gauge, to
enable the (electrically isolated) top- and bottom-
cutters to be manually revolved, compared and
adjusted to the gauge lines.
For less- mechanized workshops, the tenons are
usually deeped on a narrow band- saw machine, then
shouldered by hand as described above under Cutting
Shoulders. Note that it pays to use the widest blade
on your band saw – to avoid ‘snaking’ – and only start
the cut against the machine’s fence, then release it
and complete the cut carefully by freehand and visual
control.Mortising by hand
Figure 3.20: Although traditional hand mortise-
chopping techniques were replaced many years ago in
industry by a variety of machine methods (a mortis-
ing machine using hollow square mortise chisels
with integral auger bits being the most popular in
small- sized workshops), there are certain limitations
by machine – one of them being when a mortise is
required to be cut at an angle to the timber’s surface.
Such is the case when an oblique mortise is being cut
into a newel post. A portion of it has to be chopped
out by hand with a mortise chisel – two types are
illustrated in Figure 3.20. Apart from this, I believe
that hand mortise- chopping contains a valuable,
transferable skill- element. And for that reason, it wasHORNRAILRAIL85ºWEDGE RATIO
1 IN 12 OR 85ºSTILEGROOVE
FOR
PANEL1 IN 1.2WASTEFigures 3.19 The technique of producing wedges from tenon- material.