Basic Joints: Butt, Dado, and Rabbet
A butt joint is the simplest joint: two pieces of wood meet end-to-grain or edge-to-edge at 90°, fastened with screws, nails, or adhesive. It is the weakest joint because it relies entirely on the fasteners — there is no mechanical interlocking. It is appropriate for rough framing, carcass construction with reinforcement, or anywhere appearance is concealed. A dado joint is a three-sided channel (of uniform width and depth) cut across the grain of a board, into which a second board fits. Dadoes are used in bookcase shelves and cabinet interiors — the shelf end fits into the dado, providing both mechanical support and preventing lateral movement. A rabbet is a two-sided stepped cut along the edge or end of a board. Rabbets are used to join cabinet backs, create door lips, or form the start of a drawer runner. Dado depth: typically one-third to one-half the board's thickness. Cutting dadoes and rabbets: a dado blade set on a table saw (or repeated router passes) produces clean, flat-bottomed grooves.