Here you see the back of a framed pan face (an aluminum sign with the edges bent back to form a pan.) The dimensional letters are attached by making a hole pattern and drilling holes to accept the aluminum studs. These studs thread into the back of the letters and are pushed through the front of the pan face. A nut is threaded on to hold the letters in place. This requires quite a bit of time and precision for such small letters. The results are worth the extra effort. View the finished sign here