Inserts

Two products that go inside something else.

Divider (divider)

An egg-crate: a grid of boards that slot together with half-lap cross-laps, sized to a box's internal dimensions.

You give it the grid — X by Y spots — and it works out the boards. An X×Y grid needs X-1 cross boards and Y-1 long boards, each notched halfway through where they cross, so the assembly is rigid without glue or fasteners.

The size to give it is the box's interior, which the box's own readouts tell you. Design the box first, read its internal dimensions, then size the divider to them.

Tray (tray)

A flat floor, four border walls that capture the contents, and a configurable per-bay layout of half-lap dividers slotted into the floor.

Unlike the divider, the tray is glued, which keeps its underside flat. That matters: a tray with nothing protruding underneath will seat on top of a box divider without needing clearance cut for it, so trays and dividers stack in the same box.

Choose a tray when the compartments need a floor — small parts, tools, anything that would otherwise fall through to the bottom of the box. Choose a divider when the box's own floor is the floor.

Sizing inserts

Both are sized to fit something, and both are cut from the same shared stock as the thing they go into. Two consequences worth remembering:

• Changing the design's thickness changes the insert's boards as well as the box's walls, so the fit is maintained.
• Fit clearance applies here too. An insert that drops into a box wants a little more slack than a joint that is meant to be tight.