Compasses and Calipers
Tools for making precise measurements
During the 18th century, compasses and calipers were frequently used to measure and fit work. Many products' designs were based on the proportional relationships between their parts stepped off with a compass rather than on measurements expressed in feet or inches.
Compasses also were used to draw circles and to make geometric calculations. More importantly, compasses and calipers were the standard tools for transferring a dimension from a pattern or work piece to another location.
Coopers' compasses were large compasses with a wing that could be locked at the desired position. Many types of woodworkers used compasses of this design.
Trammel points, another form of compass, had two or more heads that could be positioned along a bar. They were used to lay out large arcs and circles.