Every joint in this arc relies on glue, geometry, or both. The dovetail is pure geometry. The dado is compression and adhesion. The mortise and tenon is long-grain surface married to long-grain surface with glue holding the bargain together.
The wedge doesn't need any of that.
A wedge creates clamping force mechanically — drives force into a constrained space until the joint locks against itself. No glue required. It can be permanent, invisible, or fully removable depending on the version you choose. It's older than hide glue and it's still earning its keep.
There are three versions. They look similar. They require completely different decisions.
Through-wedged tenon
The tenon passes completely through the mortised member and protrudes on the far side. You cut two kerfs into the protruding end. Drive hardwood wedges into those kerfs after assembly and the tenon expands against the mortise walls. The harder the joint tries to withdraw, the tighter the wedge grips. Same principle as a dovetail — the force of separation is the force of locking.
The wedge ends show on the face. This is not a defect. Arts & Crafts work, timber framing, workbenches — these pieces show the mechanism because the mechanism is the point. If you need a clean face, use a different version.
One number matters more than all the others: the kerf stops 1/8" before the shoulder line. Not at the shoulder. Not near the shoulder. 1/8" short of it. Run the kerf all the way to the shoulder and you split the tenon the moment you strike the first wedge. That 1/8" bridge is all that's holding the tenon together under expansion load.
Also: drive both wedges together, alternating strokes. Start the first wedge, start the second, first to half-depth, second to half-depth, then both to final depth. Drive one wedge completely before touching the other and you torque the tenon diagonally in the mortise. It will close and it will look fine and it will fail under load. Two extra seconds.
Fox-wedged tenon
The wedges go in before assembly. The tenon carries them into a stopped mortise — one that doesn't pass through — and as the tenon bottoms out, the mortise floor drives the wedge tips inward. The joint assembles itself as you seat it.
Nothing visible from the outside. No wedge heads, no end grain. The only thing different about this joint is that it cannot come apart. Not with heat. Not with a clamp. The fox-wedged tenon is as permanent as wood gets.
Use it where the joint will never need service and where concealed joinery is the design requirement.
The failure mode is invisible, which makes it the most dangerous joint in this arc. If the tenon seats before the wedges drive fully home — kerfs too deep, mortise too long — the joint closes and nothing locks. You have a contaminated glue surface and a joint that's weaker than a standard M&T, and you won't know it until the piece is apart.
Before you glue, the mortise floor needs a slight bell-flare — each wall angled 1° to 2° outward at the bottom. This gives the expanding tenon somewhere to go. And you do a full dry-fit. Assemble the joint completely and check that the shoulder contacts the mortised face while the wedge tips are still proud above the tenon end. If the shoulder closes and the wedges are already flush, fix it now. There is no inspection window after glue.
Tusk tenon
The tenon passes through, and a separate tapered key is driven through a hole in the protruding tail — perpendicular to its length, bearing against the face of the mortised member. Drive it in and the shoulder pulls tight. Drive it out and the joint releases. Completely disassemblable.
This is the knockdown joint of traditional furniture. A tusk-tenon workbench breaks down flat, moves in a pickup truck, goes back together with a mallet. The key hole is positioned 1/4" to 3/8" past the far face of the mortised member — that offset is what creates the draw-down force. Flush would just slide through.
In a heated shop in winter, the tenon gets slimmer. The key that was tight in October has play by February. Two mallet blows and it's tight again. This is maintenance, not failure. The joint was designed to be serviced.
Which version
Through-wedged if the mechanism can show. Fox-wedged if it must be hidden and permanent. Tusk tenon if the piece must come apart.
Not which is strongest. Which commitment the piece deserves.
The wedge geometry for all three: 1:8 to 1:10 taper, cut from long grain only. Cross-grain wedge stock splits across its width the first time a mallet touches it.
One joint, three versions, completely different relationships to time. Pick the one that matches what you're building.