No matter what I did to try to flatten my stock metal Delta table inserts I just could not get them perfect. Close, but not perfect. These Leecraft inserts are, in fact, dead flat. So it took only about two minutes to adjust them to the table height and snug fit them with the side screws. Now I can go back to measuring mortise side cut blade height off the insert rather than my jig to get the height gauge base over to the cast iron top. Sweet.