Tabletops
Breadboard end
A tongue on the top, a grooved end cap, one fixed pin in the middle, slotted pins at the edges.
Use when
- A top needs a cross-grain end to stay flat and the top must still move.
Don’t use when
- Do not pin the outer holes tight.
- Keep
- Waste, hatched on the drawing
- Dimension
- Long parts are broken. The 1 in bar is true scale.
Stock
Thickness steppers move by 1/16 in, or 0.5 mm. You can type 3/4 or 1-1/8.
Sizes
| Mark | Size | Rule |
|---|---|---|
| Tongue thickness | 1/4 in | One third of the top |
| Shoulder, each face | 1/4 in | (top − tongue) / 2 |
| Tongue length | 7/8 in | 3/4 to 1 in into the breadboard |
| Outer pin slots | 3/16 in | Elongate the outer holes 1/8 to 1/4 in across the grain of the field. The center pin is the only fixed one |
| Pin | 1/4 in | One pin in the center, tight. Outer pins ride in the slots |
Cut sequence
1Tongue the field
Tongue 1/4 in thick and 7/8 in long. Shoulders 1/4 in each face.
2Mortise the breadboard, and slot the outer pins
Center pin is fixed. Outer pins get 3/16 in of extra room across the grain.
Setup: Pin 1/4 in.
Stop when: The shoulders close and the ends of the breadboard are not glued.
3Glue the center only
An inch or two at the middle of the tongue. The ends stay dry.
4Dry-fit, then glue
Close the joint dry. Check that shoulders and faces meet, then glue. If this is a frame or a box, check both diagonals before the glue grabs.
Stop when: Dry-fit is tight with hand pressure, square, and the diagonals match.
Glue
Mostly mechanical
Strength
structural
Movement
Glue the tongue only for an inch or two at the center. The ends of the breadboard have to let the top move.