ALPHABET OF LINES

OBJECTIVES – Standard VI & Standard VIIInterpret plans, diagrams, and working

drawings.

Apply appropriate technical and graphic communication in the technological systems.

Identify Line Types for the Alphabet of Lines

Construct lines properly on drawings.

Hierarchy of lines

ESSENTIAL QUESTIONSWhy is drafting considered a universal

language?

Why is it important to recognize the alphabet of lines?

What is the hierarchy of lines?

Drafting as a LanguageDrafting is called a “universal language”

Symbols (lines and figures) have specific meaning are used.

The symbols accurately describe the shape, size, material, finish, and fabrication or assembly of a product.

Drafting as a LanguageDrafting is also known as the “language of

industry”Industry uses this precise language because

the drawings must communicate the information the designer had in mind to those who produce the product.

Why Study Drafting?Drafting is a form of graphic communication.“A picture is worth a thousand words.”

Meaning - A picture tells a story just as well as a large amount of descriptive text.

“A picture is worth a thousand words.”Steps for Drawing the Pink Panther

Draw the border and title block. Find the center of the work space. You can’t draw all the letters listed in alphabetical order. Draw everything lightly at first & then go back and darken the drawing. Darken in the eye pupils, eyebrows, & nose last to keep your draw neat. The drawing on the handout is drawn proportional. That means you can use you compass on the handout to help find center points. The measurements will not be the correct size, but you will be able to location where the center points should be on the drawing. Draw the following items in this order to make the drawing a little easier.

1. Draw A – 16 square boxes 1.5” 2. Draw B – 2” square box – This box isn’t centered on the page. The top of the box is located 5/9 of the

1.5”. 3. Draw the following letters next: C, D, E, G, I, J, the outer ear, & the bottom half to the large circle. 4. Draw the eye pupils. Start with the left pupil. Use a circle template to locate a circle that is tangent to

the left side & top of the 2” square. The right pupil is located on the outside right corner of the 2” square. Extend the right corner of the 2” square to the 1.5” line.

5. Draw M – center for M is where the eye pupil is tangent to the circle C. Bring the center point used for the left side straight across to the right eye.

6. Draw K – center for K is 3/9 of the 1.5”. K should be tangent to the eye & stops at a 20° from the center of the circle.

7. Draw top arc of nose. The center for that arc is the top of G where the 1.5” line intersects the circle. The arc size is tangent to D and will close to the center of the drawing.

8. Find point H. Swing the arc from the top center of the 2” square & the center of G. Where the two arcs intersect is point H. Must find that point on both right & left side.

9. Draw the arc for the top nose arc between the eyes. Use point H to swing an arc starting at the center of the 2” square.

10. Draw the dark part of the nose. Draw a 45° line from the center of the drawing. Where the 45° line intersects the arc for the nose part between the eyes locates the center for the arc for the opposite side of the black part of the nose. That arc size starts where the arc intersects the top of nose arc and stops on the center line of the drawing.

11. Draw the top side parts of the head. The center of this part is located by bring point H straight across to where it intersects the 1.5” line of the box below that section. The size of this arc for the head is tangent to I.

12. Draw the lower part of the chin. Use the same center point located for drawing the top side part of the head. The size of the arc is tangent to the opposite side of circle G.

13. Draw the bottom part of the head. The center point for this arc is located by bringing the top corner of the 2” square straight across to the 1.5” line. The size of this arc for the head is tangent to I.

14. Draw the lower parts of the ears. The inside lower parts are just perpendicular line from the two circles. The outside parts are going to be 60° lines tangent to the circles.

15. Draw the arc between the eyes for the top of the head. The center for this arc is the middle point between point X & point Y. The radius of the arc is located 8.5/9 of the 1.5” line up from the center of the drawing.

16. Draw arc F. Locate the center of arc F by first drawing a 45° line from the bottom corner of the 2” square to where it intersects the circle D. Next swing arc F from that intersecting point on D & from the top of the intersecting point of circle G with the 1.5” line. Where those two arcs intersect draw arc F.

17. Draw N. The center point for N is the center of the drawing. It stops straight across from point H. Draw a 45° line to make the smile.

18. Draw L. To find the center points for circle L find points X & Y. The center for the top L is from the midpoint between points X & Y. The arc starts on a 45° line from the center of the drawing and stops on the bottom of the large circle. Point X is the center for the right inter L and point Y is the center for the left inter L. The inter L starts on circle D and stops on the bottom of the large circle.

ALPHABET OF LINESIndustry standard classifying the different

types of lines used in drawings.Developed by the American Society of

Mechanical Engineers (ASME).Lines are classified by line thickness and

drawn thin or thick.Thick lines are typically drawn with a 0.7 mm or

0.9 mm mechanical pencil.Thin lines are typically drawn with a 0.3 mm or

0.5 mm mechanical pencil.

LINE TYPES

CONSTRUCTIONUsed to initially lay out a drawing.

Used for guide lines for lettering.

Draw very light and thin so they are barely visible.

Draw with a 0.5 mm pencil.

VISIBLE/OBJECT

These lines are thick and dark solid (unbroken) lines that are used on drawings to indicate the edges and details of an object.

These lines should be the most prominent on the drawing as they are drawn thicker (wider) than most other lines. We will use the 0.9 mm pencil.

HIDDEN

These lines are medium dashed lines used to indicate a surface, edge, or contour of an object that cannot be seen, or is hidden from view.The dashed lines are 1/8” long with a 1/16” space. Hidden lines will be drawn with a 0.7 mm pencil.

CENTER

These lines are thin lines made up of alternating long and short dashes. They are used to indicate the center of circles and of symmetrical features. Also as an aid in dimensioning.

The short dashed lines are 1/8” long, the space is 1/16”, & the long line ranges from 3/4” to 1 ½”. Lines will be drawn with 0.5 mm pencil

SECTION

Section lines are thin “cross hatching” lines used in sectional views to symbolize different parts of an object or different materials from which an object is manufactured.

Section lines are normally drawn at a 45° with a 0.5 mm pencil.

DIMENSION, EXTENSION, & LEADER

These lines are thin lines (0.5 mm)used for dimensioning purposes.

Dimension and leader lines generally end with arrowheads and are accompanied by a number indicating a size or location dimensions.

Extension lines aid dimension lines by extending the surface of the object so it can be dimesioned.

CUTTING PLANE OR VIEWING PLANE

These lines are very thick lines (0.9 mm) that indicate where an imaginary cutting plane passes through an object, for viewing or sectioning purpose.

Arrowheads on both ends of the line point to the surface to be viewed.

BREAK

These lines are used to shorten a view, or to eliminate repetitive details when an entire view is not necessary.Short break lines are thick wavy freehand lines.Long break lines are thin straight zigzags.

PHANTOM

These lines are thin lines used to indicate alternate positions of moving parts, lines of motion, adjacent parts and repetitive details.

They are similar in style to a Cutting Plane Line, but much thinner in weight.

Hierarchy of Line It is not uncommon for line types to

coincide or overlap in a drawing.

When visible lines, hidden lines, or center lines coincide in the same view, a preferred line is illustrated.

That chosen line is determined by what is called the Precedence of Lines.

Hierarchy of Line This list ranks the line type precedence from

highest to lowest:Object or visible lineHidden lineCutting plane lineCenter lineBreak lineDimension and extension linesSectioning lines

Hierarchy of Line In the example you can see where lines coincide with one another line from the front view to the side view.

Hierarchy of Line The “X” lines are object lines which overlap the hidden line of the circles (holes). The object line has precedence over the hidden line which means the object line is drawn.

Hierarchy of Line The “Y” line is an object line which overlaps the center line of the large circle. The object line has precedence over the center line which means the object line is drawn.

Hierarchy of Line The “Z” line is a hidden line. Although the center line for the small circle (hole) is in front of the hidden line, the hidden line has precedence over the center line and is therefore shown instead of the center line.

REVIEWWhy is drafting considered a universal language?

Even though people around the world speak different languages, the graphic language (symbols & line types) has remained common.

Why is it important to recognize the alphabet of lines?The lines in the Alphabet of Lines are used to describe

shape, size, hidden surfaces, interior detail, and alternate positions of parts.

Each conveys a particular meaning on the drawing.What is the hierarchy of lines?

The order in which lines are drawn when more than one line type is located in the same location on a drawing.

REVIEWWhat line starts and ends with a dash?

HIDDEN LINEWhat lines should be the most prominent

on the drawing?OBJECT LINE

What line is drawn the lightest and thinnest for laying out the drawing?CONSTRUCTION LINE