Q: Why do companies make 8" dado blades? If a saw is made for a 10" or 12" blade, that is the optimum surface cutting speed for that saw, and that is where it operates the safest. When you change to a dado set (whether it be a set or a wobbler type blade), you are compromising your safety on that saw because you are now cutting much more material and you have to be more attentive. Now you change to an 8" blade and you are running at a reduced cutting speed (20 percent on a 10" and 33 percent on a 12" saw). I would think that this reduced cutting speed and the wider blade would seriously compromise your safety on the saw! Why don’t companies make 10" and 12" dado sets to maintain more safety on the saw?
A: Machine manufacturers actually determine the appropriate sized dado that can be used on their machine. They determine this given the design of the arbor, power transmission system and motor, along with safety considerations and other factors that influence the best size for their machine. Some 10" saws actually will only allow 6" dadoes. Dadoes remove a lot more material than a blade does and are harder on the saw than a standard blade. You should only use the size the saw manufacturer recommends.