beam compass

noun

, Drafting.

1. a compass having adjustable legs, set perpendicular to the paper and sliding along a horizontal bar so as to permit the drawing of large circles.

beam compass

noun

1. an instrument for drawing large circles or arcs, consisting of a horizontal beam along which two vertical legs slide Also calledtrammel

Word History and Origins

Origin of beam compass¹

First recorded in 1775–85

Example Sentences

These lines are struck with great rapidity, and with mathematical truth, by an instrument called a "beam compass," in the use of which this workwoman is most expert.

From Project Gutenberg

The "Odd Job" Tool.—A most useful special tool, which combines in its make-up a level, plumb try-square, miter-square, bevel, scratch awl, depth gage, marking gage, miter gage, beam compass, and a one-foot rule.

From Project Gutenberg