Joinery 101: Cut Dado Seams to Any Size With an Adjustable Jig
Dado joints have been used for centuries to create cabinets and bookshelves. Add this joint to your woodworking repertoire with a fixture and a store-made router. With this setup, you will be able to make precise cuts of different widths every time.
Dado is a square-walled, flat-bottomed channel cut across the grain of the wood, into which another piece of wood will fit snugly. It is a simple connection but extremely effective. For example, when building a 3/4 “wood bookshelf, you must cut a 3/4” wide dado in the vertical section so the shelf can fit into it. Parts are assembled with glue and screws.
The video above demonstrates how to set up your router and use a simple jig and clamp to make the dado cuts. The fixture consists of two rails that hold the router along the entire length of the cut and maintain the same width. Dado joints are only effective when the two pieces of the wood stock are tightly aligned with each other.
Router Basics: Dado | Carpenters magazine