Leroy Lettering Set are used in drafting and other roles where standard uniform characters are required, such as for title blocks and annotations, special notes on engineering drawings, or on photographs. The set typically consists of a set of Leroy templates, a scriber, and set of pens (see photo).
A Leroy scriber is shown in the diagram below. An adjustable scriber produces letters with any slant from vertical to 22 1/2 degrees forward from a single template; a fixed scriber produces only vertical letters. Both scribers consist of a tracing pin, pen socket, socket screw, and a tail pin. Scribers may also have a screw-in mount for technical fountain pens (set shown above).
Templates are made of laminated plastic with the characters engraved in the face so that the lines serve as guide grooves for the scriber. The height of the characters, in thousandths of an inch, is given by a number on the upper right-hand side of the template. For example, 3240-500CL indicates a No. 500 template. The entire number and letter designation identifies the template in the manufacturer's catalog. The range of character heights offered by a standard set of templates is from 80 (0.08 in. or 5/64 in.) to 500 (0.5 in. or 1/2 in.). The scale at the bottom of each template has the zero in the center and is arranged for proper spacing in relation to character heights. The distance between each scale division represents the center-to-center distance of normal-width letters.
Lettering templates are an alternative to the Leroy Lettering approach, offering essentially the same kind of mechanical lettering but using a different guide (see picture). The templates are offered in U.S. and metric sizes, usually corresponding to the technical pen line size they are designed to be used with, for example an 0.25 works with a .25 technical fountain pen. They work well with a straight edge, eliminating some of the steps required with the Leroy equipment.