## Procedure

• Problem 3-19 & 3-20 are in Inches, problem 3-21 is Metric.
• Do as many drawings below as you can in the time available.
• Follow the same procedures as the previous tutorials.
• Dimension these drawing.
• For a closeup open problem3_19_to_3_21.pdf and zoom in as needed.
• Center the drawings, scale, print, staple together and hand in to be marked.
• See Hint For Problem 3-19 at Bottom Of This Page!

## Hint for 3-19 – How to find the center of arc “R”

• First draw as much as you can.
• From the center of the 0.25 radius arc (center mark on the left) draw a 1.88 radius circle.
• 1.88 is derived from adding the 0.25 and 1.63 arcs
• 0.25 + 1.63 = 1.88
• From the center of the 4.18 diameter circle (center mark on the right) draw a 0.96 radius circle.
• 0.96 is derived from finding the radius of the 4.18 diameter circle and dividing by 2 to get the radius then subtracting for the 1.13 radius arc
• 4.18 ÷ 2 – 1.13 = 0.96
• The “R” radius arc is drawn from the center to the TANGENT of the R3.0 circle.
• The R1.13 radius arc is drawn from the center to the TANGENT of the 4.18 diameter circle.