Drafting Compass for Drawing Circles & Arcs are used in Mapping & Navigation

Use a drafting compass to draw arcs & circles:

A compass has two arms one containing a needle (shoulder needle) and the other a graphite lead. To draw a circle and arc with the compass adjust the width/spread (distance between needle point and lead); place the needle point at the center where the two center lines intersect; rotate the compass by twisting the thumb and forefinger to produce the circles line. It is important to sharpen the lead to a chisel point to produce lines of even thickness while rotating the compass. Generally soft lead (F or HB) are used in compasses so the circle are drawn as dark object lines.