Part 3 — Gauge Attachment for a Pocket Rule
Reading edition
The base of the gauge A is cut from a block of hard wood, about 2-1/2 in. long, 1 in. wide and 3/8 in. thick. A notch is cut in one side to admit the rule and the wedge B, which has a slot that slides on a pin in the base. A small metal clip keeps the wedge in place. The gauge can be readily set on the rule at any mark.