In Moxon's time both the letter board and the paper board were made alike, similar to the present paper board; and he strongly recommended to have the board made of one piece, without a joint: they are now different from each other. The letter board is made of two deals, about an inch thick, and the smallest size allows a demy chase to lie upon it without hanging over the edges; the deals are joined together on the under side by two dovetailed tapering tongues inserted into dovetailed tapering grooves, the contrary way to each other; and these tongues project below the bottom, so as to serve as feet for the board, to a depth rather more than equal to the height of letter, and allow the board to be placed upon a bulk, or upon another letter board, upon which pages or small jobs are placed, without the bottom of the board touching the face of the type. If the boards shrink, or the joint opens, the aperture can be immediately closed up again, by striking the edges with a mallet, and driving the tongues up tight.
The usual sizes of letter boards in a printing office are Demy and Royal; but when works on larger paper are printed, it is necessary to have boards of a corresponding size. The Demy boards are 26 inches by 22; the Royal 30 inches by 26.