This is a tool to help you understand the type setting process. You can see a demonstration of the type setting process in a Common Press tour on Arthur Ross Gallery's Instagram from last summer.
The composing stick is used to hold the type, spacing, and leading as you set type. The adjustable arm is set at a 40 pica line length:
A scan of a font of type and spacing. Print at 100% on 8.5 x 11 in paper and cut apart into blocks.
Layout of the California Job Case (1 typical layout of a type drawer): print at 11 x 17 and use to organize your type.
Leading creates the space between lines of type. Print to scale on 8.5 x 11 inch paper, and trim to match the line length of your composing stick (40 pica).
A Printer’s Ruler, or Line Gauge - print to scale on 11 x 17 paper:
A scan of 12pt type to scale, set in the composing stick: