I use the Tru Angle file then coarse and fine stones to sharpen my Zwickey 2- and 4-blade Deltas. Yes, the groove is wide enough for the blade to move within it. Two things to keep in mind. First, you will need to take off some of the metal where the blade is triple laminated near the tip with a hand file before you attempt to sharpen on a Tru Angle file or stone. Otherwise, the head won't sit flat on the stone its entire length. Second, the hones work much better with a straight edged blade like a Delta than they do on a convex blade shape like an Eskimo, which requires alternately lifting and lowering the blade on the hone to sharpen its entire length.