You can use a contour gauge to mark the irregular cuts required to notch a tile around a door casing, but there is a much simpler method. Place a tile next to the casing and use it as a thickness gauge for a handsaw as you trim the bottom of the casing (see drawing). Casing trimmed, the tile will fit under it without any complicated cuts. This trick also works with resilient tiles, but when using one, be sure to turn it upside down to keep from marring its finished surface.
John Molnar, Moorestown, NJ