I am having difficulty replacing the interior doors in my 35-year old ranch house. I have used the measurements from the old doors (which fit OK) to determine how much to plane off the inner edge, and where to place the hinges. I am on my third door, and it seems that every time I replace one it takes about 5 tries to get it to fit correctly, because the door won't close entirely (it bucks on the hinge and leaves a one foot gap). Any suggestions?