Chapter 2 Using Drawing Tools & Applied Geometry

TOPICS Using of Tools Basic Line Types Applied Geometry

Using the Tools

Function of the Tools Tools Shape to be drawn 1. T-square Straight line 2. Triangles 3. Compass Arc, Circle 4. Circle template

Using the Compass 1. Locate the center of the circle by two intersecting lines. 2. Adjust the distance between needle and lead to a distance equal to radius of the circle. 3. Set the needle point at center.

Using the Compass 4. Start circle. Apply enough pressure to the needle, holding compass handle between thumb and index fingers. 5. Complete circle. Revolve handle clockwise.

Draw a Horizontal Line 1. Press the T-square head against the left edge of the table. 2. Smooth the blade to the right.

Draw a Horizontal Line 3. Lean the pencil at an angle about 60o with the paper in the direction of the line and slightly “toed in”. 4. Draw the line from left to right while rotating the pencil slowly.

Draw a Vertical Line 1. Set T-square as before. Place any triangle on T-square edge. 2. Slide your left hand to hold both T-square and triangle in position.

Draw a Vertical Line 3. Lean the pencil to the triangle. 4. Draw the line upward while rotating the pencil slowly.

Draw a line at 45o with horizontal 1. Place 45o triangle on the T-square edge and press them firmly against the paper. 2. Draw the line in the direction as shown below.

Draw a line at angle 30o and 60o 1. Place 30o-60o triangle on the T-square edge and press them firmly against the paper. 2. Draw the line in the direction as shown below.

Draw the lines at 15o increment 0 deg. 15 deg. = 30 + 45 deg 30 deg. Already demonstrated. 45 deg. 60 deg. 75 deg. = 30 + 45 deg 90 deg. Already demonstrated.

Draw the line passing through two given points 1. Place the pencil tip at one of the points. 2. Place the triangle against the pencil tip. 3. Swing the triangle around the pencil tip until its edge align with the second point. 4. Draw a line. A B A B Given

Basic Line Types

NOTE : We will learn other types of line in later chapters. Basic Line Types Name according to application Types of Lines Appearance Continuous thick line Visible line Continuous thin line Dimension line Extension line Leader line Dash thick line Hidden line Chain thin line Center line NOTE : We will learn other types of line in later chapters.

Visible lines represent features that can be seen in the Meaning of Lines Visible lines represent features that can be seen in the current view Hidden lines represent features that can not be seen in the current view Center line represents symmetry, path of motion, centers of circles, axis of axisymmetrical parts Dimension and Extension lines indicate the sizes and location of features on a drawing

Example : Line conventions in engineering drawing

Class work page (11): practice no. 4 , 7 , 10 Home work page (10): practice no. 5 , 6 page (11): practice no. 1 , 5

Applied Geometry

To Bisect a Line Practice :take AB=100 Given 1. Swing two arcs of any radius greater than half-length of the line with the centers at the ends of the line. 2. Join the intersection points of the arcs with a line. 3. Locate the midpoint. r1 Given A B r1 A B Practice :take AB=100

To Bisect an Angle Practice : take an angle =30 Given 1. Swing an arc of any radius whose centers at the vertex. 2. Swing the arcs of any radius from the intersection points between the previous arc and the lines. 3. Draw the line. A B C (not to scale) Given A B C r1 r2 r2 Practice : take an angle =30

To draw the line parallel to a given line with a specified distance Given distance = r r Practice: the line= 120 the distance r=20

To draw the line parallel to a given line with a specified distance Given distance = r r r Repeat

To divided an straight line to equal parts: Known: line AB C A B Practice : AB= 100 5 parts

To transfer an angle: Known: angle ABC M R M1 N N1 R1 Practice: the angle ABC=45

To draw a triangle Known: triangle’s member AB , BC, CA R2=BC R1=CA Practice: AB=110 BC=90 AC=70

To draw a regular pentagon Known: length of AB D R=AB R1=OF R2=BG F A B G O Practice: AB=60

To draw a hexagonal shape inside a circle Known: circle of radius R C D R R A B E F Practice: R=60

To divided a circle into 7 equal parts: Known: the diameter of the circle 1 N 2 7 R A B C O 6 3 5 4 Practice: D=120

To divided a circle into 8 equal parts: Known: the radius of the circle C 1 7 5 The same way we find points 7 & 8 r r not to scale 4 2 O 6 8 3 Practice: R=50

H.W Page 14 : no. (4) / take AB=80 , the distance between the lines =20 Page 16 : no. (10)/ take D=80 page 16: no. (12)/ take AB=50 Page 17: no. (15)/ take AB= 80 Page17: no. (16)/ take AB=100

FILLET AND ROUND Round Sharp corner Fillet Round

FILLET AND ROUND To draw the arc, we must find the location of the center of that arc. How do we find the center of the arc?

To draw an arc of given radius tangent to two perpendicular lines arc radius r r r

To draw an arc of given radius tangent to two perpendicular lines arc radius r center of the arc Starting point Ending point Practice: the angle=90 R=30

To draw an arc of given radius tangent to two lines arc radius r r r + +

To draw an arc of given radius tangent to two lines T.P.1 T.P.2 Practice: angle=120 , 50 R=30

H.W Page 18:no. (18)/ take the radius R=30 The distance r= 20 The length of the line AB=70 The line AB located at distance (50) from the center of the arc (O)

To draw a line tangent to a circle at a point on the circle Given C

When circle tangent to other circle Tangent point R1 C1 R2 C2 R1 + R2 The center of two circles and tangent point lie on the same straight line !!!

To draw a circle tangent to two circles I + Given + C2 + C1 Example

To draw a circle tangent to two circles I Given Two circles and the radius of the third circle = R + + C2 C1

To draw a circle tangent to two circles I Given Two circles and the radius of the third circle = R R + R2 center of the arc R + R1 R2 C R R1 + + C2 C1 Repeat

When circle tangent to other circle Tangent point R1 R2 C1 C2 R2  R1 The center of two circles and tangent point must lie on the same straight line !!!

To draw a circle tangent to two circles II + Given + C2 + C1 Example

To draw a circle tangent to two circles II Given Two circles and the radius of the third circle = R + + C2 C1

To draw a circle tangent to two circles II Given Two circles and the radius of the third circle = R R R2 R1 + + R – R2 C2 C1 R – R1 C Repeat

To draw a circle tangent to two circles III Given Two circles and the radius of the third circle = R R2 R1 + C2 + C1 R + R2 R – R1 C

Practice The distance O1 O2= 60 R1=30 R2=20 R=30 ,70,50

H.W 1. صفحة رقم (25): تمرين رقم (2.15) مصباح

To draw an approximate ellipse Given Major and minor axes

To draw an approximate ellipse Given Major and minor axes Repeat

Practice 1. Major axes AB=100 Minor axes CD=50 2. Page 27: practice no. (2.24)

How to Keep Your Drawing Clean Do Don’t

H.W 1. صفحة رقم 25 : تمرين رقم (2.20)