Beam Compasses

The BEAM COMPASS is used for drawing circles with radii larger than can be set on a pivot joint or bow compass. Both the needle- point attachment and the pen or pencil attachment on a beam compass are slide-mounted on a metal bar called a beam. The slide-mounted attachments can be locked in any desired position on the beam. Thus, a beam compass can be used to draw circles of any radius up to the length of the beam. With one  or  more  beam  extensions,  the  length  of  the radius of a beam compass ranges from about 18"  to 70".