It seems as if installing drywall corner bead ought to be a snap: Just hold it flush to the intersecting walls, and staple or screw it to the framing. Corner bead, though, sometimes has a mind of its own, and it can twist into shapes that don’t want to lie flat against a wall. That’s where the squaring device shown in the drawing at right comes in.
It’s simply a piece of 1/2-in. plywood or particleboard that has a square notch cut out of it. My crew and I use a chainsaw file to cut a radius into the inside corner to accommodate the bead’s radiused edge. Pressed against the bead as we work up and down the wall, this gadget keeps the corner bead where we want it.
Mike Nathan, Hailey, ID