Tools for Cutting Dados in 6x8 Treated Lumber

Table Saw Dados

• A table saw is the best tool for cutting dadoes in most material. Grooves up to 3/4 inches wide and several inches deep can be cut in one pass. A table saw dado blade is made up of several stacking blades which are combined to create the desired width of notch. For wider dadoes, or grooves that need to be deeper than an inch or two, multiple passes will give the best results. Increase the depth of the blade a little each time, or adjust the rip fence slightly to widen the dado.

Router Dados

• A router with a straight flute bit can be used to create dadoes up to 2 inches deep and 1/2 inch wide. The router will require a fence or straight edge clamped to the 6-by-8 to ride along for a straight line. Alternately, a router table with a fence can be used to created the dado, much like a table saw. Multiple passes are typically required for dadoes more than 1/2 inch deep. Have a helper assist you to maintain balance when passing long beams through a table router.

Circular Saw

• Although a stack dado cannot be used with a hand-held circular saw, large dadoes can be created. Use the saw in conjunction with a fence, or straight edge to make 1/8-inch wide cuts at the desired depth about 1/8 inch apart. These wood fins are then broken out with a hammer. Use a wood chisel to smooth the bottom of the dado if needed. A radial arm is another circular saw that can be used in the same way for short, cross cut dadoes.

Hand Tools

• A sharp flat wood chisel can be used to cut any length or size of dado but is the most time consuming method. Mark the sides of the dado and cut along the edges by driving the chisel down, with its flat bottom facing out on the line. Cut the dado by removing the material from between the lines a layer at a time. You can take up to 3/16 inch in one pass while still maintaining control to prevent splitting or digging in, where the chisel tilts into the wood, taking a deeper than desired cut.