If you have many lines of lettering to do, you will find a lettering instrument, such as the Ames lettering instrument, shown in figure 3-43, view B, quite useful and timesaving. The top-left section of figure 3-43, view B, shows how to use this instrument in conjunction with a T square to draw properly spaced horizontal guidelines. You insert the point of your pencil through one of the holes, and the instrument slides along the T square as you move the pencil across the page. The enlarged drawing of the instrument in the lower part of the figure shows the details of how the instrument is used. Notice the three rows of holes in the circular disc of the instrument. The holes in the center row are equally spaced guidelines. The two outside rows are used for drawing both capital and lowercase guidelines. The left row gives a proportion of 3 to 5 for lowercase and capital letters, and the right row gives a proportion of 2 to 3.

The design of the Ames lettering instrument permits you to use it for lettering ranging in height from 1/16 to 5/16 in. These various heights are attainable by rotating the circular disc within the outer section of the instrument. The numbers along the bottom edge of the disc are used to set the instrument for a particular letter height. A number aligned with the index line on the outer section of the instrument indicates the height of the lettering in 32ds of an inch. In figure 3-43, view B, the number 8 is aligned with the index; therefore, the distance between the capital letter guides produced by this setting is 8/32 in. or 1/4 in.

By standing the Ames lettering instrument on its greater sloping side, you can use it for drawing guidelines for inclined lettering that slope at an angle of 67 1/2 degrees with the horizontal. (See the upper-right portion of fig. 3-43, view B.)