Compasses and dividers
can be used for a number
of tasks ...
by Jack Burgess
C
ompasses and dividers are very similar. Basically, com-
passes are used to draw circles, while dividers are used to
transfer measurements. For example, you could transfer
measurements from a scale drawing to the material being used
to build the model. Many of us (if you are old enough) used a
compass in school (with a lead pencil into one leg) to draw circles.
But the real difference between the compasses and dividers is
whether both points are metal (a divider) or if one point is a pencil
lead (a compass).
Combination drafting compasses are typically equipped with
both a piece of pencil lead to draw circles and an extra needle
for use as a divider. Since this article in not about drawing
circles, I’ll be using the term “dividers” when talking about
taking measurements, and “compasses” when discussing cut-
ting discs of styrene.
The simplest dividers utilize a friction movement to hold the
two legs in position. This might work for transferring measure-
ments on drafting project but doesn’t work well for modeling
Drafting tools for modeling part 2
The Tool Shed - 1
1: I have two dividers/compasses, both of which are combina-
tion bow compasses. The smaller one has a maximum spread
of about 2" and is used primarily for transferring measure-
ments. The larger 6" combination bow compass has an effec-
tive radius of about 5½".
1
purposes. Modelers instead need a “combination bow” com-
pass (1) that has a wheel which moves the legs in and out. This
wheel can be located between the legs (as on the compasses
in Photo 1) or on the side of one leg. This type of compass or
MRH-Oct 2013
