# Slots and Tabs

Slot and tab construction involves interlocking parts like a 3D puzzle. Tabs on one piece fit into slots on another, aligning the parts automatically. When glued, bolted, or clamped together, this method creates fast, rigid assemblies without complex tools.

#### How It Works

* CAD parts are designed with matching cutouts and tabs.
* Cut from flat sheet stock (metal, polycarb, plywood).
* Tabs insert into slots and are fastened with screws, rivets, glue, or welding.

#### Pros

* **Fast Assembly:** Self-aligning joints reduce the need for jigs.
* **Repeatable:** Great for building multiple identical bots or testbeds.
* **Good for Non-Metal:** Works well with plastic or wood prototypes.

#### Cons

* **Hard to Modify:** Once joined, the structure isn’t easily reconfigurable.
* **Flex Risk:** Thin materials may wobble or deform under load.
* **Cutting Precision Needed:** Slots and tabs must be toleranced correctly for your cutting process.

#### FTC Tips

* Add \~0.1–0.2mm clearance between tabs and slots depending on cutter type.
* Use interlocking fingers or “keyed” features to lock parts rotationally.
* Add fillets or dog-bones to inner corners to match laser/waterjet cut radius.
* Secure tabs with nylon lock nuts or rivets—design so they sit flush to avoid snagging.