A dado is a U-shaped square cornered cut in the surface of a board that is made across the grain. Use the miter gauge and the safety grip as you Would for any crosscutting operation.
Click to see larger view Figure 3-25. This is the first cut you make when you need an extra-wide dado. When more than one piece is involved, make this same cut on all pieces before changing the setting. Extra-Wide Dadoes-When you need a dado that is wider than can be accomplished with the dado accessory at maximum width, proceed as follows: Place a spacer on the rip fence near the front of the table and lock the fence so the distance from the spacer to the dado will be the edge distance of the cut you need. Butt the end of the work against the spacer and make the first cut. Next, move the rip fence so the distance from the spacer and the outside surface of the dado accessory will be the width of the cut you need. Make a second cut (Figure 3-26). Then just keep making overlapping passes until the waste stock between the first two cuts has been cleared away.
Make a second pass the same way after you have flipped the work. The two cuts will line up perfectly. Matching Dado Sets-These dadoes, might be required, for example, when building a bookcase with shelves that are supported on both sides by a midpoint partition. Place a spacer on the rip fence near the front of the table and lock the fence so the distance from the spacer to the dado will be the edge distance of the cut you need. Make the first cut. Be sure to keep the workpiece level. After the first cut, the work is flipped over and a second pass is made. You know that the two dadoes will be perfectly aligned. The cuts must be shallow enough to leave at least 1/3 the stock thickness uncut.