Joint
Cut a woodwork joint where two boards overlap, such as a finger (box), butt, dowel, housing, rebate, mortise and tenon, halving, CNC tab and slot or Cabineo joint, or fit a drawer slide.
- Joint JPart workspace toolbar
Joint cuts real woodwork joints for you. Model both boards full size, so they overlap where they meet. Joint cuts the joint out of the overlap and works out the sizes.
Board 1 is the board the joint is cut into, such as the side of a bookcase or the leg of a table. Board 2 is the board that goes into it, such as the shelf or the rail.
How to use it#
- Model the two boards full size, overlapping where they meet.
- Click one board, Shift-click the other, then click Joint or press J. With nothing selected, SchoolCAD picks the first two parts that overlap.
- Click the type of joint. SchoolCAD starts with a finger joint for thin sheets, and a housing or halving joint for thicker boards.
- Check Board 1 and Board 2 (goes in) in the lists. Click ⇄ to swap them. (For a finger joint they are Panel 1 and Panel 2.)
- Set the sizes, or keep the ones SchoolCAD fills in.
- Check the preview, then click ✓.
Joint types#
| Joint | What it is | What you can set |
|---|---|---|
| Finger | Fingers that lock together at a corner (a box joint), for laser-cut boxes. | Fingers: how many in total (an odd number looks best). Clearance: a small gap so the fingers fit (0.1 to 0.2 mm for the laser). Start with: which panel has the first finger. |
| Butt | Board 2 is cut back so its end sits flat against board 1. Hold it with screws, nails, glue blocks or brackets. | Nothing. |
| Dowel | A butt joint held by hidden dowels, glued into both boards. | The dowel size (Ø6, Ø8 or Ø10, and 30, 40 or 50 long), How many, and how far they go Into board 1. |
| Housing | Board 2 sits in a groove across board 1, like a shelf in a bookcase. At the end of board 1 it becomes a rebate: a step cut along the end. | Depth: a third of the thickness is usual, or half for a rebate. |
| Mortise & tenon | A tongue (the tenon) on the end of the rail fits a slot (the mortise) in the leg. The strongest frame joint. | Tenon thickness, Shoulders (how far the tenon is set in from each edge), and the Depth, or tick Through. |
| Halving | Where the boards cross, each loses half its thickness, so their faces end up level. For frames, cross rails and egg-crate dividers. | Top half: which board keeps its top half. |
| Tab & slot | For CNC-cut plywood (cabinets, van fitouts). Tabs on board 2 go into slots in board 1, with screws beside the tabs to pull the joint tight. The number of tabs follows the length of the joint, so it keeps working when a panel changes size. | Tabs: how long, and about how far apart. How many and how far the first is from each end. Slots: Through, or Blind so the far face of board 1 stays whole (a top under a mattress); a blind slot at board 1's edge gets a narrower tab, set in, so it does not break out. Screws: two per tab, one, or none, and how far from the tab. |
| Cabineo | Lamello Cabineo 8 connectors: a pocket in the inside face of board 2 and a Ø5 hole in board 1, both cut by the CNC, so nothing shows outside. For drawer boxes and fronts. | How many (SchoolCAD spaces them under 250 mm apart, or 100 on short joints) and how far from the ends. Other face puts the pockets in the other face of board 2. |
| Drawer slide | A Selectlok 3076 heavy-duty slide (1500 mm, full extension) between a cabinet wall and a drawer side, with all its bolt holes: counterbored on the outside of the wall and the inside of the drawer, so the bolt heads sit flush. The slide is made as its outer, middle and inner members, ready to move in the Assembly. Leave the slide's 19.5 mm gap between the two panels. | Locking (the locking slide sits further back), Height of its middle above the bottom of the drawer side, Set back from the front, and ⇅ if the drawer opens the other way. |
Tips#
- Until you type a size, the box shows the size SchoolCAD worked out, and it changes when the boards change.
- The note under the sizes explains the joint, such as which dowels to buy and how deep to drill.
- Dowels are made as parts, so they appear in the cut list, the exploded view and renders. Untick Show the dowels as parts if you do not want them.
- A finger joint shares the overlap out as fingers, so the box keeps the outside size you drew.
- You can model a whole project with the boards overlapping, then add the joints at the end. Check lists every overlap, with a Make a joint button that starts a joint between those two parts.
- The assembly instructions use your joints to say how each part joins on.
- Cabineo connectors and drawer slides are made as bought parts, so they are counted in the bill of materials. They go in the sub-assembly of the board they are fitted to.
- For Tab & slot and Cabineo, board 2 comes in square to board 1's face. If a board runs on past the joint (a drawer side under one lid that stops at the next), set Comes in to X, Y or Z.
- Add a Cabineo only where you can still reach it with the driver at that point in the build. Where a later panel would close it in, use Tab & slot with screws.
- After the tab-and-slot joints, add Dogbones to every panel so the slots' inside corners fit the router cutter.
- Panels made with Box can take their sizes and positions from the parameters table, so the whole cabinet, with its joints, follows when you change a size.
If it does not work#
- These boards do not overlap. Model both boards full size so they overlap where they meet, then add the joint. Make board 2 longer, or move it, so it goes into board 1.
- Board 2 should be the one that ends at board 1 (the shelf or rail). Swap the boards. Click ⇄.
- Board 2 goes right through board 1. Use a halving joint, or shorten board 2 so it stops at board 1.
- The overlap is not a simple box, so the joint may look odd. Joint works best where two plain, square boards meet. Look for a cut or a rounded edge inside the overlap.
- The dowel holes nearly go through board 1. Use shorter dowels or a thicker board.
- The gap between the wall and the drawer side is … mm; this slide needs 19.5 mm. Move the drawer side, or make the drawer narrower, so the slide fits.
- The wall and the drawer side overlap: leave the slide's gap between them.