The nine joinery modes
What each mode is for
Joinery — also called connectors in 3D-printing circles — determines how the split pieces connect after printing. Each mode has independent size, length, count and tolerance controls so you can compensate for your filament's shrinkage. Defaults: 5 mm pegs, 8 mm long, 0.2 mm tolerance, 2 per cut.
- Square pegs — square pegs extruded from one face, matching sockets in the other. Press-fit straight off the printer, no glue. The default for most jobs; square so they cannot rotate.
- Dovetails — slide-together trapezoidal rails. Useful for thin-walled pieces where pegs would split the wall. Available on single-axis splits only, because a corner piece in a multi-axis grid would have to slide in two directions at once.
- Tenon / mortise — one large square tenon per face, woodworker style. More glue surface than several small pegs.
- Finger / box joints — alternating rectangular fingers, no separate insert. The most glue surface per area on long flat cuts.
- Magnet pockets — cylindrical recesses on both faces sized for disc magnets (default 6 × 3 mm, the common N52 size). Glue magnets in; pieces snap together and come apart.
- Dowel holes — matching cylindrical pockets for a separate wooden or printed dowel.
- Screw joints — a clearance hole with a counterbore for the head runs from the outside of one piece to the cut, into a heat-set insert pocket in the other. Placed only where one side is thin enough for the screw to reach (shells, hollowed models); the preflight check says so before you split.
- Custom connector — load any STL as the connector (Z is the insertion axis). It is sunk half its height into each piece, the pocket is the connector grown by the tolerance, and the part is written to the zip with a sheet of every copy. Use it for a dog-bone, a proprietary clip, or a connector matched to a competitor's library.
- None — clean cuts with no joinery. For glue-only assembly, or when the cut shape itself provides the interlock (brick, pyramid or jigsaw).
The picker groups them by what you need after printing: printed insert (pegs, tenon, finger, custom), you supply (magnet, dowel, screw) and cut-in (dovetail, none).
Which to use when, glue by material and the clearances that fit: How to join 3D printed parts. The cut surface itself can interlock too — see cut shapes.