Australian Wood Review - June 2018

82 Australian Wood Review

TECHNIQUE

The third method, derived from the last,

again relies on two holes at the base of

each kerf, each offset to the edges of the

tenon (photo 3). With the holes drilled

in this position the outside kerfed part

worked more like a hinge, moving freer

with little stress on the kerf.

Method four, with kerfs cut at an

angle from the top of the tenon

and heading away towards the edge

(photo 4), is somewhat similar to the

third method. With less material in

the tenon at the end of the kerf, the

outside portion moves more freely,

almost hinging at that point.

Method five does not employ any

angle of the mortise. Instead, a small

amount is removed from the top and

bottom of the width of the tenon

and a kerf, like the first, cut parallel

to the edges of the tenon (photo 5).

Not necessarily the most common of

methods, but one seen while working

in the UK many years ago.

Testing process

To ensure consistency the mortises

were cut in a somewhat unorthodox

manner. Rather than produce a

traditional mortise for each one and

then cut the wedge relief afterwards,

the mortises were cut as housings, the

wedge relief parts carefully marked

out and pared to a line with a chisel.

The outside cheek part was then

glued back on to create the mortises.

This method also allowed me to

create accurate, matching hardwood

wedges for each method. Whilst doing

all this I decided to include another

mortise for a fox wedged tenon,

curious to know what happens inside

this mysterious joint (photo 6).

All tenons were glued and wedged in

the same fashion; glue was brushed onto

the tenon and mortise cheeks, tenon

inserted and clamped into position.

A small amount of glue was brushed

onto each face of the two wedges, then

hammered into the kerf (photo 7).

A small hammer is my preferred tool,

making sure to evenly tap each wedge

home. The glued and clamped up test

mortises were left for 24 hours for

the PVA to fully cure. The test piece

was put through the thicknesser the

following day to reveal the test results.

Method one shows definite splitting

at the bottom of each kerf and while

this was the most noticeable for all

methods tried, neither split goes

beyond the tenon shoulder (photo 8).

Method two, with the two centred

holes at the end of each kerf also

shows some splitting (photo 9). The

third method, with the holes moved

towards the outside of the tenon and

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