PROTRACTOR HEAD: The protractor head rotates by degrees allowing
angle selection. A lock button secures the head at the selected angle. The
head maintains a true angle throughout motion over the drawing surface.
The protractor head houses the scale mechanism that holds the scales into
Figure 2-11 shows the location of the protractor head.
Figure 2-11. A
SCALE MECHANISM and REMOVABLE SCALES: There are a variety of
scales available for the drafting machine. Not only do scale faces vary, but
so does the composition of the scale. Scales can be made of clear plastic,
wood, or metal. Two removable scales attach to the scale mechanism at right
angles to each other via male and female dovetail fittings, In fitting the
scales to the mechanism, you should hear an audible click. An elongated slot
on the mechanism allows minor angular adjustments to the scale. Do not
force a scale into the fitting.
Figure 2-12 illustrates how dovetail fittings connect.
Figure 2-12. Dovetail
Continued on next page