When the time comes to replace a letter plate, many people look to find an exact match to the size of their existing one. It would, of course, be ideal if an exact size match could be seen, but in most cases, this is difficult to achieve. Unfortunately, letter plates for wooden doors have never been manufactured to standard sizes, and there can even be variations in the same model from the same manufacturer. The sand-casting process is not exact, so these dimensional variations can occur between different manufacturing procedures. A smear of grease on the mechanism and spring of any letter plate is something we recommend because it will preserve it from corrosion and early failure.