The sliding dovetail, as already noted, is an excellent option, in my
A variation of the dovetail AND mortise & tenon, in combination, an
oriental (method) joint long used in building pagodas, may be another
excellent option in your case. Cut a slimmed down version of a
dovetail, ie. about 7 degree angle cuts instead of the normal angles.
Cut a "V" shaped slot, about 4 degrees, in the end of the dovetail.
Cut your mortise slot with about 10 degree angled sides, ie. a bit
wider than your slim dovetail. Cut a "V" shaped wedge, about 10
degrees. Insert wedge into modified mortise as you insert modified
dovetail, so that wedge slips into the slot of the dovetail. As you
further insert dovetail into mortise, the wedge will further insert
itself into the slot, and at some point the wedge will begin to push
sideways against the two sides of the slotted dovetail. When dovetail
is completely inserted, the wedge will have applied pressure against
dovetail sides such that the dovetail sides will have, in turn, snugged
themselves against the mortise sides. No glue required, but certainly