Joinery and Fit
Tenon's products are held together by cut joinery — geometry, not fasteners. This page explains what it generates and which settings move it.
Finger joints
Box corners are finger-jointed: alternating fingers and sockets, each one material-thickness deep, so the two walls interlock and register themselves square. The pitch is a parameter on the products that use it; the depth always comes from the stock thickness.
Tabs and slots
A captured bottom does not sit in a groove — it carries tabs that pass through slots in the walls. That way the floor is located in all three axes by geometry alone, and the box cannot rack.
Plain tabs are recessed slightly below the outer face (Tab recess) so nothing protrudes on a finished surface. Some products hook their tabs instead, so a pin can draw the joint tight.
Pinned versus glued
Two boxes of the same size can be built two ways:
- Glued (Project Box) — the joints go together with adhesive and stay together. Fewer parts, simpler cut.
- Pinned (Pinned Project Box) — the corners carry hooked tenons drawn tight by a separate flat pin, so the box knocks down and reassembles. More parts: each hook needs its pin.
Pick glued for a box that will live assembled, pinned for one that has to ship flat or come apart.
Half-laps
Dividers and trays interlock with half-lap crossings: each board is notched halfway through where it meets another, so the grid assembles flush. This is why a divider's boards do not need any fasteners either.
Kerf, clearance and fit
Three settings decide whether the parts you cut actually go together:
| Setting | What it does |
|---|---|
| Cutter diameter | Slots widened so a round cutter can enter; internal corners cannot be sharper than this |
| Fit clearance | Slack added to mating features so a joint can be assembled |
| Joint fit | The named preset (e.g. slip fit) that sets how tight the interlock is |
The cutter cannot cut a sharp internal corner, so a socket cut with a 3.175 mm bit has 1.6 mm radii in its corners, and a square finger will not seat fully into it. Products handle this in their geometry; what you control is telling Tenon the truth about the cutter.
If joints are too tight, raise fit clearance a tenth or two. If they are sloppy, lower it — but check the cutter diameter first, since an overstated cutter widens every slot.
Test before you commit
Cut one corner in the real material before cutting a whole job. Fit is the one thing the preview cannot tell you: it depends on your machine, your bit and your plywood, and a tenth of a millimetre either way is the difference between a press fit and a gap.