Keys Mortise Through Tenon Mortised Timber King Post Collar ...

or
 four
 inch
 tenons,
 one
 or
 two
 keys,
 and
 keys
 of
 either
 white
 oak
 or
 ipe
 (a
 tropical
 hardwood).
Currently,
samples
of
wood
cut
from
the
joints
are
being
tested
to
provide
input
strength
values
for
the
mathematical
 equations.

These
models
will
provide
predicted
joint
strength
values
for
comparison
to
the
experimentally
tested
joint
strengths
for
model
validation.
Below
 is
 a
 photograph
 of
 a
 joint
 tested.
 
 The
 joint
 is
 loaded
 upward
 in
 the
 testing
 machine
 causing
withdrawal
of
the
tenon
from
the
mortised
timber
by
upward
movement
of
the
machine
cross‐head
on
the
end
to
the
tenoned
timber
and
the
holding
down
of
the
mortised
timber
with
steel
tubes
and
bolts.
The
red
arrows
indicate
the
load
directions.
Tenoned
Timber
Steel
Tube
Tenon
Courtesy
of
Lance
Shields
Below
are
photographs
(courtesy
of
Lance
Shields)
of
some
tested
joints.

The
first
three
photographs
are
of
a
Douglas‐fir
joint
with
an
11
inch‐long
tenon
and
two
keys.

The
first
photograph
shows
the
joint
before
 testing,
 the
 second
 photograph
 shows
 the
 joint
 in
 the
 testing
 machine
 under
 tension
 loading
(notice
 the
 separation
 between
 the
 mortise
 and
 tenon
 member),
 and
 the
 last
 photograph
 shows
 the
failure
of
keys
after
testing.
Joint
before
Test
































Joint
during
Test











Keys
after
Test
(Bending
&
Crushing)
The
next
three
photographs
show
a
white
oak
joint
with
a
four
inch‐long
tenon
and
two
keys.

The
first
photograph
shows
the
joint
before
testing,
and
the
second
and
third
photographs
show
the
joint
during
and
 after
 testing
 (note
 the
 tenon
 relish
 underneath
 the
 left
 key).
 
 Typically,
 joints
 subject
 to
 tension
tests
 with
 11
 inch
 tenons
 produce
 key
 crushing
 and
 bending
 failures
 while
 the
 joints
 with
 four
 inch
Cross‐head
Mortised
Timber
Key