46 ELEMENTARY WOODWORKING 
needed for circles and ares of circles. Each triangle con- 
tains one right angle, the one on the left being known 
as a thirty—-sixty triangle because the two remaining 
angles are thirty degrees and sixty degrees respectively. 
The one on the right is called a forty-five-degree triangle 
because it has two forty-five-degree angles. 
The position of T square and triangle when drawing 
vertical lines is that shown in the sketch, the line being 
drawn from the T square 
upward. Horizontal 
lines are drawn from left 
to right. 
The rule used in me- 
chanical drawing is 
called a scale, and should 
not be used for draw- 
Fic. 61. The Triangles used in Mechan- ing lines. Its purpose 
ical Drawing 
is measuring. 
In making a drawing the first step is to determine 
the spacing. The size of the paper may be measured, 
the number of views are known, and also the size of 
each. The views should be so arranged that the spaces 
between will be in good proportion. It is a good plan 
to make first a free-hand sketch, putting on dimen- 
sions and figuring the spaces before beginning actual 
work on the mechanical drawing. Fig. 62 at a shows 
