Drawing Compass - History and Types of Compasses

A technical drawing tool named a drawing compass is used to draw circles or arcs. This tool is also known as a pair of compasses or simply a compass. It can also be used for measuring distances or, more precisely, distances on maps. Drawing compasses are also used in navigation, mathematics, drafting, and many other disciplines.

Materials for which compasses are made are usually plastic or metal. The drawing compass has two parts connected by a hinge so the circle's radius can be adjusted and changed. Usually, at the end of one part is a needle, and at the end of another is a pencil.

First, drawing compasses was found in the archeological digging of ancient Rome. Every drawing compass before the eighteenth century didn't have a pen but a needle, so it scratches the surface. By the twentieth century, drawing compasses were spread widely throughout the world.

Today, because of the development of computer-aided design software or CAD, the usage of drawing compasses is reduced. However, it still teaches technical drawing and geometry in schools and colleges.

The handle of a drawing compass is about 1.25 centimeters long and is made so that users can grip it between their thumb and pointer finger.

A measuring compass can have two different types of legs. One type is the adjustable leg that supports a needle, and another is a steady, immovable leg that serves for adjustments in drawing circles. A screw on a hinge also holds those two legs in position. That hinge is also adjustable, and the compass will be more accurate if the screw is tight. On a steady leg of a drawing compass is a needlepoint. The function of a needle the point is to be the center point of a drawn circle. The pencil's lead purpose is to draw a circle on a material. A nut is also used to adjust the pencil lead to be in place.

A drawing compass can draw circles on a specific material (wood, metal, plastic…) by putting a needle in a circle's center that should be drawn and rotating it around while keeping the same angle on the hinge. If the hinge is moved, the radius of a circle can be adjusted.

Compasses can also be used for measuring distances on maps. Those compasses are called dividing compasses, with two needles instead of one. The measurement can be done by measuring how many times the fixed compass can fit in some distance.

Types of Drawing Compasses

There are a couple of variants of drawing compasses.

Beam Compass

A beam compass is made of brass or wooden beam and is used for drawing circles larger than a regular compass.

Scribe Compass

This type of compass is the most simple by form. Carpenters use the scribe compass to scribe a circle instead of drawing it.

Loose Leg Divider

These dividers are made of all forged steel and used to scribe circles. Loose leg wing dividers also provide stepping-off repetitive measurements with particular accuracy.

Proportional Compass

The military used the proportional compass (the sector) from the sixteenth to the nineteenth century to do calculations. It is a tool consisting of two rulers equal in length and joined by a hinge.