A dado blade is a specialized saw blade used to cut a dado, groove, or rabbet into a piece of dimensional lumber or sheetgoods. There are two main types: Wobble Blade and Stacked Dado Head. A Wobble Blade consists of a single blade held between two beveled faces which act as arbor plates. Typically these faces are graduated and have an arrow to indicated how much rotation of the faces is needed to achieve a particular width of cut. Wobble blades tend to be less expensive but of poorer quality than Stacked Dado Heads. Using a wobble blade in a Radial Arm Saw is discouraged. Dado Blade Basics A Stacked Dado Head typically consists of a set of two or more "standard" saw blades which are then separated from each other by the addition of smaller, two toothed, blades called chippers. A good Dado set will include several different thicknesses of chippers and several thin metal spacers used to fine tune the width of cut. Freud Tools - Pro Dado Set The use of either of these styles of dado blades is recommended for skilled carpenters only, as they can easily "get away from you". They are never to be used on anything other than a Table or Radial Arm Saw. Some Table Saws have changeable arbor screws to allow for the use of wider dado blades.