Clamp a piece of 1/2 plywood to the door, flush on the edge on the high side of the bevel. This is the side of the door opposite the stop. Lay the template from the new lock on the plywood and mark the center of the 2-1/8" bore. (Should be 2-3/8" from the edge of the door and plywood). Make sure it's at the same height and centered with the latch bore in the edge of the door. Drill through the plywood and the door with the new size holesaw. When you are half way through the door, clamp a fresh piece of plywood on the opposite side of the door and finish drilling. Otherwise, you'll splinter the face of the door when the holesaw breaks through. Yes, you'll need a 2-1/8" bore for a Schlage lockset. Yes, it is one of the better quality locksets out there.