JT-002Joints & Assembly
The mortise and tenon without glue
Why traditional joinery holds without adhesive: the drawbored peg, the wedged tenon, and what glue-free framing means for repair a century later.
Entry checked on · kept by the tally · ~3 min read
Open a kominka frame and you will find almost no glue: the joints hold because the wood is shaped to hold them, not because a bond was asked to do the carpentry. The mortise and tenon is the grammar of that system, and its two locking devices, the peg and the wedge, are what keep a frame honest for a hundred years without a drop of adhesive.
The joint itself
A tenon is the tongue cut on the end of one member; the mortise is the slot chopped into the other. Shoulders on the tenon seat against the mortise face and carry the compressive load; the tongue inside resists twisting and racking. Cut to a snug fit, the joint is already strong in every direction except withdrawal, and the locking devices exist to answer exactly that one direction.
The drawbored peg
The drawbore is the elegant trick: the peg hole through the tenon is bored a millimetre or two closer to the shoulder than the hole through the mortise cheeks. Driving the tapered peg through both forces the joint closed and keeps it under permanent tension. The peg is visible, honest, and can be driven out again when the frame needs to come apart, which is why a working atelier notebook treats the peg as a signature: the carpenter who drawbores leaves proof that the joint was closed by wood and not by hope.
The wedged tenon
Where the tenon passes through the mortise and shows on the far side, a wedge driven into a saw kerf in the tenon expands it into a dovetail inside the mortise. The joint cannot withdraw; the wedge end shows as a small dark rectangle that reads as a mark of craft rather than a flaw. Both devices share the same virtue: they are mechanical, inspectable and reversible.
What glue-free means a century later
A frame pegged rather than glued can be dismantled, repaired and re-erected, which is precisely what happens to kominka today when they are moved. Glue has its place in modern work, but a joint designed to lock without it carries a second life inside the first one.
What glue costs a frame
Glue is not wrong; it is simply a different contract. A glued joint is closed for good, and when the house needs to open it, the only way in is a saw. The pegged frame was designed by carpenters who expected the building to be taken apart and re-erected, which is exactly what happens to kominka today. The joint that can be opened is the joint that survives a move; the glued one becomes a broken edge and a shorter member.
Reading an old joint
An old pegged joint tells you how it was made before you touch it: the peg end shows as a small square or circle, slightly darker than the member it locks, often a hair proud of the surface after a century of the wood shrinking around it. A peg driven flush and left is the mark of a careful hand; a peg that stands out proud was driven later, or worked loose and re-seated. Either way, the joint is telling its history in the peg face, and the reader who can see it knows how the frame was closed.
The card, filed
The mortise and tenon without glue is the foundation joint of inspectable carpentry: shaped wood, closed by a peg or a wedge, openable by the same means. If the joint cannot be taken apart, the frame cannot be repaired; the old carpenters built that truth into the hole placement.
