Selected Bibliography Architectural Graphics | Page 12

TRI ANGLES Triangles are drafting aids used to guide the drawing of vertical lines and lines at specified angles. They have a right angle and either two 45° angles or one 30° and one 60° angle. 411 to 2411 lengths are available. • 8" t o1011 1 engths are recommended. ~ • Small triangles are useful for crosshatching small areas an as a guide in handlettering. See page180. d • Larger triangles areuseful inconstructing perspectives. 0 90° • The 45°-45° and 30°- 60° triangles can be used in combination to produce angular increments of 1 5°. See page 19. • Triangles are madeof cle scratch-resistant, nonar, yellow acrylicto allow a transparent, undistorted ing viewthroughto the work below. F luorescent orange acrylic triangles are also availablefor greater visibility on the drafting surface. • Machined edges should be polished for precision and to facilitate drawing. Some triangles have raised edgesfor inking with technical pens. • Inner edges m be beveled to serve as finger lifts. ay \\\ \ \ \ \ \\ \ \ \ \ \ \ \ \ \ \ \ '\,\ \ \ \ \ \ \ \ \ \ \ \ "\ \ \ \ \ \ \\ ~ ~ \\ \\ \ \ \ "\ \ \\ \ \ \ • Keep triangles clean by washing with a mild soap and w ater. • Triangles should not be used as a straightedgefor cutting materials. \ \ \\ \ \ \ \ \ \ \ \ \ \ "~\ ~~ ,./,-/ ,/' 6 I ARCHITECTURAl GRAPHICS Adjustable Triangles Adjustabletriangles have a movable leg that is held in place wit ha thumbscrew and a scale for measuring angles.These instruments are useful for drawing such inclined lines as the slope of a stair or the pitch of a roof.