Leveling the Keys
Make two small blocks – about ¾” [19mm] thick and 2” [50.8mm] long. Take a block and slide it backwards under key #1 until it touches the bottom surface of the key. The idea is to wedge the key in position so it cannot dip below 2 3/16” [55.5mm] above the table. Make sure that the block doeesn't move the key higher than 2 3/16" [55.5mm]. Mark the position of the block on the keyframe – remove it and put a drop or two of CA glue on its bottom surface, and re-install on your mark. Do the same for the last key at the top end of the keyboard. Do not use so much glue that you permanently glue the blocks to the keyframe.
