I had to add finger grips to two sliding doors. I was very nervous about drilling my doors as I would have to drill them while they are hanging in place. After testing the drill on a few pieces of wood, it became apparent that holding the drill in place without support would be too difficult. So I made a bracket out of 3/4" plywood, attached the bracket to the door and drilled the holes with no problem. The holes were very smooth and the finger pulls went in very easily with no problems.