The bridle joint is also referred to as
an 'open' or 'slot' mortise-and-tenon
joint. This is because the mortise is
open-ended and the tenon may be slid
into it sideways. The joint can be used on
corners, either cut square or mitred, where
it's signifi cantly stronger than a halving
joint by virtue of its large gluing area.
Tools you'll need to cut
bridle joints:
• Try square
• Pencil
• Mortice marking gauge
• Tenon saw or Pullsaw
• Coping saw
• Router with straight cutter
It's most useful, however, for connecting
middle legs to continuous top rails on
tables, where breaking the rail to form a
pair of tenons would weaken the structure
unnecessarily. This form of the joint is known
as the T-bridle. It's a relatively simple joint to
make, with the slot being cut fi rst and then
the tenon made to fi t it. The proportions
used are the same as for a standard
mortise and tenon, so when joining two
timbers of equal thickness, the slot should
be set centrally and should be no more than
one third of the timber's thickness.
This is also an easy joint to cut with
machine tools. You could use a mortiser to
cut the slot, but a bandsaw is the ideal tool.
Using the rip fence, you can saw a slot in
seconds with total accuracy. To remove the
waste from the tenon component, use a
radial arm saw or a sliding mitre saw.
1] Start by marking the position of the joint
on the tenon member with a try square
and a sharp pencil
2] Use the mortise member and the try
square to mark the wood's exact width on
the tenon member
3] Extend the lines all round the workpiece
using the try square. They should meet
exactly if the wood is square
4] Mark the depth of the slot on the mortise
member. You can make it a little deeper
and then plane off the end once the joint is
complete, to produce a neat finish
5] Set a mortise marking gauge to the
width of your chisel. The wood is 19mm
thick, so I chose a 6mm wide chisel as
closest to one third of its thickness
6] Centralise the gauge and mark both
sides of both components. Always work
from the same face of the workpiece to
minimise any inaccuracies
7] To make the marked lines more clearly
visible before cutting the joints, run a
sharp pencil along them
8] Fix the mortise member vertically in a
vice. Using a fi ne-point saw, cut down on
the waste side of the marked lines
9] Use a coping saw to remove most of the
waste from the slot. Take care not to cut
beyond the base line
10] Square off the base of the slot with a
chisel, cutting down to the marked line
and working from both sides of the wood
11] Now cut the matching tenon. Make sure
the cuts are vertical and within the waste
area. Don't run over the gauged lines
12] You can use a router to remove most of
the waste. Fit a wide straight cutter and
plunge down to the gauged lines in stages
13] Clean up the base of the joint on both
sides of the wood with a wide-bladed
chisel held fl at to the surface
14] Test the fi t of the joint, and make any
necessary adjustments with a chisel or
abrasive paper
15] The fi nished joint. If you marked and
cut the mortise a little over-deep, plane
the projection fl ush for a perfect fi nish
trevah davis
