  thumb|a beam compass and a regular compass thumb|a thumbscrew compass for setting and maintaining a precise radius a compass (or pair of compasses) is a technical drawing instrument that can be used for inscribing circles or arcs. as dividers, they can also be used as tools to measure distances, in particular on maps. compasses can be used for mathematics, drafting, navigation, and other purposes. compasses are usually made of metal or plastic, and consist of two parts connected by a hinge which can be adjusted to allow the changing of the radius of the circle drawn. typically one part has a spike at its end, and the other part a pencil, or sometimes a pen. prior to computerization, compasses and other tools for manual drafting were often packaged as a "bow set"a current vendor's product with interchangeable parts. today these facilities are more often provided by computer-aided design programs, so the physical tools serve mainly a didactic purpose in teaching geometry, technical drawing, etc. ==construction and parts== compasses are usually made of metal or plastic, and consist of two parts connected by a hinge which can be adjusted to allow the changing of the radius of the circle drawn. typically one part has a spike at its end, and the other part a pencil, or sometimes a pen. ===handle=== the handle is about half an inch long and is made of plastic. it provides the user with good grip between the pointer finger and the thumb. ===legs=== there are two types of legs in a compass. the straight or the steady leg and the adjustable one. both have different purpose, the steady leg serves as the basis or support for your needle point. while on the other hand, the adjustable leg can be altered by drawing different sizes of circles. ===hinge=== the screw on your hinge holds the two legs in its position; the hinge can be adjusted depending on your desired stiffness. the tighter the screw the better the compassâ performance. ===needle point=== the needle point is located on your steady leg, serves as the center point of your circle. ===pencil lead=== the pencil lead draws the circle on a particular paper or material. ===adjusting nut=== holds the pencil lead in place. ==uses== circles can be made by fastening one leg of the compasses into the paper with the spike, putting the pencil on the paper, and moving the pencil around while keeping the hinge on the same angle. the radius of the circle can be adjusted by changing the angle of the hinge. distances can be measured on a map using compasses with two spikes, also called a dividing compass. the hinge is set in such a way that the distance between the spike
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