The 8" Delta stacked dado is dismal. I set it up to make a 1/4" box joint. Could probably have done better with a chisel. One of the outer blades is a larger diameter than the other, making a ragged bottom in the groove. Tried the same thing set at 3/8". Joint wouldn't fit right. Turns out the dado is really about .42" wide. Further setups revealed the chippers are not a uniform diameter. Don't waste your money on this. Spend it on a good one, like maybe a Freud or a Jesada. You pay for what you get. I wasted (my money) on this. I'm going back to my old Craftsman 7" wobble-head dado. The Delta may become an anchor for my boat. Maybe it can do that right!