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Study Unit

The Alphabet of Lines

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Essentially, drafting involves the creation of lines. Whether the lines are used to form letters or partsof a drawing, consistency is the key to success. The lines that you create as a drafter are your meansof communicating with others. In a drawing, for example, the numeral 5 must be made distinct fromthe letter S, and an object’s centerline must look different from a line showing an actual edge of theobject. These distinctions are possible only if a consistent system of making letters and drafting linesis put into general use.

Lettering can be an especially important test of a drafter’s ability. You’ll need to letter on practicallyall of your drawings. Therefore, lettering is a skill often used as a gage for evaluating a drafter’s abil-ity. Of course, drawing objects is the true focus of any drafting work, so learning how to create theproper lines on a drawing is just as critical as becoming competent in lettering.

When you complete this study unit, you’ll be able to

• Describe the accepted techniques of lettering

• Identify the different types of lines used in drafting

• Recognize the drafting lines used in mechanical and architectural drawings

Preview

iii

THE TECHNIQUE OF LETTERING . . . . . . . . . . . . . . . . . . . . . . . . 1Our Standard AlphabetPreparing to Learn LetteringPractice in LetteringProofing Your Work

TYPES OF DRAFTING LINES . . . . . . . . . . . . . . . . . . . . . . . . . . 10Lines in Mechanical DraftingLines in Architectural Drafting

LEARNING CHECK ANSWERS . . . . . . . . . . . . . . . . . . . . . . . . 19

Contents

v

THE TECHNIQUE OF LETTERING

Our Standard Alphabet

The Origins of Writing

Our system of writing—the way we express ideas using letters and simple forms—has taken thousands of years to develop. The hieroglyphicwriting, or picture writing, of the ancient Egyptians forms the basis ofseveral different alphabets. The Phoenician, Hebrew, and Arabic writingsystems as well as the Devanagari system of India can all be traced backto Egyptian hieroglyphic writing. The Phoenician alphabet of 22 letterseventually gave rise to the Greek alphabet—from which, in turn, the an-cient Romans derived their alphabet. As the Roman empire expanded,the Romans spread Latin across Europe. As a result, the Roman alphabetbecame the system of writing now popularly used throughout WesternEurope and the Americas.

Keep It Simple, Keep It Smooth

Although the Roman alphabet provides us with a standard set of letters,the appearance of those letters can vary greatly. A typeface is a particulardesign or style of lettering. Figure 1A shows some examples of severaldifferent typefaces. Figure 1B shows a simplified typeface first popular-ized during the latter part of the nineteenth century by an Americannamed C. W. Reinhardt. Use of this plain, uncomplicated design hasmade lettering a faster and more consistent process in drafting. Andeven though the Reinhardt style is plain, there’s still plenty of room forvariety. Note the obvious visual differences between vertical, lower case,inclined, and so on.

Think of all the time that would be consumed if a drafter had to use theOld English typeface or the thick and thin lines of the Old Roman style.Luckily, Reinhardt’s simplified style is now commonly used throughoutcommercial industry. Thus, drafters of today can communicate throughtheir technical drawings using smooth, consistent, easily formed strokes.

Preparing to Learn Lettering

The only way to learn lettering is by making letters. First, though, let’s getprepared.

The Alphabet of Lines

1

Sharpening Your Leads or Your Pencil

A sharp point can be placed on your mechanical pencil leads by using a sharpener. Wood pencils may be sharpened with a knife and thenpointed to a cone shape with a sandpaper pad. Figure 2 shows this proce-dure for sharpening a wood pencil.

Forming Your Pencil Point for Lettering

After you’ve sharpened your lead, form a slightly dull point by round-ing the end of the lead on a piece of scrap paper. Doing so will allow thelead to move smoothly over the paper without breaking.

FIGURE 1—Can you imagine trying to letter a drawing using the Old English typeface shown in 1A? Obviously, thetypeface shown in 1B, with its simpler strokes, makes lettering much easier.

FIGURE 2—The way to sharpen a wood pencil using sandpaper is shown here. Regardless of how you sharpen,however, your lead should end up with a conical shape like that pictured in 2C.

2 The Alphabet of Lines

Learning to Apply the Lettering Strokes

Whenever you’re lettering, keep in mind the following tips.

• Use moderate pressure on your lead to get the proper density intoyour letters.

• Rotate the pencil with your fingers after each letter. This will keepthe point sharpened evenly all around and will help you maintain auniform width of line. Neglecting to rotate the pencil will cause thelead to become flat on one side, which will spoil the appearance ofyour letters.

• Try to make your lines as wide as those shown in the samples thatfollow.

• Don’t hesitate to resharpen when your lines begin to get too wideand fuzzy.

• Never trace over your letters. If you’re not happy with a letter,erase and do it over.

And Finally—A Word about Arrowheads

As shown in Figure 3A, arrowheads are produced by as many as fourstrokes, but you can learn to form an arrowhead in one continuous mo-tion. As indicated in Figure 3B, the length of a properly drawn arrow-head is approximately three times its width (W). Normally, the lengthwould be about 3⁄16 inch (3⁄16′′), or about 5 millimeters (5 mm). However,the length of an arrowhead should never be less than 1⁄8′′ (or about 3 mm),and the same length must be used for all arrowheads on any given drawing.

Look again at the stages for drawing an arrowhead in Figure 3A. In architectural drafting, arrowheads are usually formed within only twostrokes—that is, the type of arrowhead featured in block 2 is the arrow-head most commonly used. Further, instead of the arrowhead at eitherend of a dimension line, a heavy slash mark or a dot is often preferred in

FIGURE 3—The blocks in 3Ahave been numbered tocorrespond to the order ofstrokes for forming anarrowhead in four stages.When you get good at it,though, you’ll be able todraw an arrowhead in onecontinuous motion. Payspecial attention to thelength and width of yourarrowheads.

The Alphabet of Lines 3

some architectural companies. Figure 4 shows how these alternatives toan arrowhead would appear on architectural drawings. The slash shouldform an angle of 45 degrees (45°) where it connects with the end of a di-mension line. Also, all the slashes on a drawing should be drawn in thesame direction.

Practice in Lettering

Before you actually begin lettering, study the illustrations in Figure 5.These illustrations show the order of strokes in successive steps for all let-ters and numerals. The letter or numeral to be formed is shown at the farleft in each column of the chart. The successive steps, or strokes, in letter-ing are shown in the blocks to the right. It will take from one to fourstrokes to complete each letter and each numeral.

FIGURE 4—In architectural drafting, a slash mark or a dot may be preferred instead of an arrowhead to mark eachend of a dimension line.


One by one, for each letter and numeral, analyze the order of strokes. Be-low each row of strokes in Figure 5 are five empty blocks. Fill in each ofthese blocks with the complete letter or numeral of the type directly abovethe empty row. Each time, reproduce the strokes appropriate for that par-ticular letter or numeral. The letter A is shown at the top of the chart asan example for this exercise.

FIGURE 5—Refer to the order of strokes each time you letter until the order comes naturally for each letter and numeral.You can practice the strokes by filling in the row of empty blocks below each letter and numeral in the chart. Anexample of how to fill in these empty blocks is shown using the letter A at the top of the chart.


As you work through the exercise in lettering strokes, keep in mind thefollowing suggestions.

• When the stroke requires an up-and-down motion, you should beable to form the mark better by stroking down rather than up.

• When the stroke requires a horizontal motion, right-handers gener-ally prefer moving left to right; left-handers usually find a right-to-left motion more comfortable.

• In making circular strokes, experiment to see whether clockwise orcounterclockwise motions feel better for you.

Continue practicing the order of strokes by reproducing the additionaltips on lettering listed in Figure 6.

When you’ve finished the exercise in Figure 6, go on to the exercise fea-tured in Figure 7.

For some additional practice in lettering, complete the exercise in Figure8.

Proofing Your Work

After you’ve finished your lettering exercises, proof your work by con-sidering the following points.

• Do you have any “slants” mixed in with what should have beenvertical strokes? If you do, make the necessary corrections.

• Did you overlook line width as you worked to perfect the shape ofyour letters? The width should be close to that of the samples. Cor-rect any letters or numerals that are irregular.

• Are your letters black in appearance, or are they a fuzzy gray?Markings that are gray, which usually indicates that a hard leadhad been used, will show only faintly on a reproduction. Remem-ber, a shop technician won’t see your original drawing—only theprint. All lettering, therefore, should be black.

• Did you apply enough pressure to get the graphite into the fibers ofthe paper? Even a black letter may be dark only on the surface ofthe paper. This surface layer of graphite can wear away during thereproduction process, leaving behind a weak line.


FIGURE 6—Read through the lettering tips listed here. Then, practice the order of strokes by reproducing the list oftips in the space provided.


FIGURE 7—Reproduce the lines of words, letters, and numbers in the space provided.


FIGURE 8—Reproduce the notes, callouts, dimensions, and arrowheads shown on the left side of the figure in theappropriate spaces on the right side.


Now, take a few moments to review what you’ve learned about letteringby completing Learning Check 1.

TYPES OF DRAFTING LINES

You’re already familiar with how we use the alphabet to create mes-sages. Lines form recognizable letters, which in turn are used to formwords. The result is communication. Drafters, however, frequently uselines to convey information without letters. Various types of draftinglines exist. These drafting lines function like the words of a language—acertain line represents a certain concept or idea. Knowing what theselines mean is key to understanding the language of drafting. Drafting isa universal language—understood by people from all nations—because,worldwide, drafters have agreed on what the lines indicate. We’ll beginexploring the universal language of drafting by studying the conven-tions for drafting lines. As you work through this section of your studyunit, keep a pad and a straightedge or ruler handy. As you study eachline, you should practice drawing it. We’ll look first at the line standardsas they apply to mechanical drafting.

Learning Check 1At the end of each section of The Alphabet of Lines, you’ll beasked to check your understanding of what you’ve just read bycompleting a “Learning Check.” Writing the answers to these questions will help you review what you’ve learned so far. Please complete Learning Check 1 now.

Fill in the blanks in the following statements.

1. The slash at the end of a dimension line should be drawn at an angle of _______ degrees tothe dimension line.

2. Before using a newly sharpened lead, you should _______ the end of the lead on a piece ofscrap paper so that the lead will travel smoothly and without breaking.

3. The length of a properly drawn arrowhead is approximately _______ times its width.

4. If you observe the suggested order of strokes, it should take only one stroke each to formthe numerals 1, 2, 3, and _______.

5. While arrowheads are the norm in mechanical drafting, _______ drafters often prefer to useshort, heavy slashes to mark the ends of dimension lines.

6. To avoid flattening out the lead on one side, you should _______ the pencil after formingeach letter.

7. If your lead is too hard, the markings will usually be colored _______.

8. If you observe the suggested order of strokes, it should take no more than _______ strokesto form any letter in the alphabet.

Check your answers with those on page 19.


Lines in Mechanical Drafting

The standard drafting lines used by a mechanical drafter aren’t necessar-ily the same as those used by, for example, an architectural drafter. Electrical and electronic drafters also have their own sets of special sym-bols. A line with an arrowhead, for instance, may represent a relay on anelectrical schematic. For a mechanical drafter, however, an arrowheadmay be associated with a dimension line used on a drawing. In contrast,an architectural drafter may prefer slashes or dots for use with dimen-sion lines. In all cases, a neat and accurate design, drawn with correctsymbols and lines, is the stamp of a professional drafter.

Table 1 shows the types of lines that a mechanical drafter commonlyuses. Look at the name of each line first, then note how thick it is com-pared to the other lines. Also, check the grade of lead recommended todraw the line. Read the line’s description and application to see what theline is intended to represent. Once you’ve studied the line, sketch it onyour scratch pad. Try to sketch your lines so that they resemble the repre-sentations shown. (This practice—duplicating the lines while you revieweach line’s description—is an excellent way to master this special lan-guage of drafting.)

In Table 1, note that visible lines and hidden lines are the only linesshown that represent actual surfaces. (A visible line represents an edgethat an observer would be able to see; a hidden line represents an edgethat’s concealed from view.) The other lines shown in the table all haveto do with revealing dimensions or measurements on drawings.

Some of the lines in mechanical drafting appear very similar to eachother. For example, note the subtle differences between centerlines andphantom lines. As you examine Table 1, you may wonder how someonecan tell the difference between hidden lines and stitch lines. The answeris that a person probably can’t tell the difference; that is, unless the stitchlines are called out as they are in the example. Thus, a drafter sometimesuses letters along with drafting lines to transfer information.


Table 1

LINE STANDARDS AS APPLIED TO MECHANICAL DRAFTING

Name Convention Description and Application Example

Visible Lines (Thick) Heavy, unbroken lines.Used to indicate thevisible edges of anobject.

Hidden Lines (Thin) Thin lines made up ofshort, evenly spaced1/8′′ dashes with 1/32′′spaces. Used to indicateconcealed edges.

Centerlines (Thin) Thin lines made up oflong and short dashesalternately spaced andconsistent in length—long dashes: 3⁄4′′–11⁄2′′,short dashes: 1/8′′, spaces:1/16′′. Used to indicatesymmetry about an axisand location of centers.

Dimension Lines (Thin) Thin lines with anarrowhead at each end.Used to indicatedistance measured.

Extension Lines (Thin) Thin, unbroken lines.Used to indicate extentof dimensions.

(Continued)


Table 1—Continued

Table 1



Section Lines (Thin) Thin, solid lines. Used toindicate an imaginarycut or sectioned surface.

Leaders (Thin) Thin lines with anarrowhead or a dot atone end. Usually drawnat a 30°, 45°, or 60°angle. Used to indicatea part or dimension or tomake some kind ofreference.

Phantom or Datum Lines(Thin)

Thin lines made up of arepeating pattern of onelong dash and two shortdashes. The dashes areevenly spaced and thelines end with longdashes. Used to indicatethe alternate position ofparts, a repeated detail,or a datum plane.

Stitch Lines (Thin) Labeled, thin lines madeup of short, evenlyspaced dashes. Used toindicate stitching or sewing.

Long Break (Thin) Thin, solid, ruled lines withfreehand zigzags. Usedto reduce the overall sizeof the drawing or theamount of detail revealedwhen delineating an object.

(Continued)


Lines in Architectural DraftingThe line standards in Table 2 apply specifically to architectural drafting.You’ll find that architectural drafting permits individual styles anddoesn’t hold so rigidly to conventions. For example, an object line maybe drawn thicker than normal when a shape or feature requires specialemphasis. Mechanical drafting, on the other hand, requires that rules forline thicknesses are closely followed when creating drawings. Table 2shows some examples of lines commonly used in architectural drafting.As you study Table 2, note the similarities and differences between theseline conventions and the ones you’ve examined in Table 1. You can “naildown” the conventions and distinctions by looking at various mechani-cal and architectural drawings to see how all these drafting lines are actu-ally used.

Table 1—Continued

Table 1



Short Break (Thick) Thick, solid, freehandlines. Used to indicate a small break in thedrawing.

Cutting or Viewing Plane

Viewing Plane Optional

Thick, broken lines witharrowheads indicatingwhich section or plane isbeing viewed or taken

Cutting Plane for Complex or Offset Views

Thick, broken lines. Usedto show offset.Arrowheads indicate thedirection viewed.


Table 2

LINE STANDARDS AS APPLIED TO ARCHITECTURAL DRAFTING


Outlines (Visible) Heavy, unbroken lines.Used to emphasize theperimeter or outline ofan entire drawing orobject. Should be madewith an H lead andheavy pressure.

See Figure 9

Object Lines (Visible) Medium to thick,unbroken lines. Used toindicate any singleobject within a drawing.Should be made with a2H lead and moderatepressure.

See Figure 9

Hidden or Invisible Object Lines

Made like regular objectlines, but thinner and broken. Dashes: 3/16′′–1/4′′; spaces: 1/16′′–1/4′′.

See Figure 9

Dimension Lines Thin, solid linesterminated with anarrowhead, heavy slash,or dot at each end.Used to indicatedistance or locationmeasurement. Shouldbe made with a 4H leadand moderate pressure.Arrowheads may bemade with a 2H or Hlead.

See Figure 10

Extension Lines and Centerlines

Made like dimensionlines. Extension line usedto indicate the extent ofa dimension; centerlineused to indicate thecenter of an object.

See Figure 10

(Continued)


Table 2—Continued

Table 2

LINE STANDARDS AS APPLIED TO ARCHITECTURAL DRAFTING


Texture Lines (Coded for different materials)

Appearance of linesvaries. Used to indicatethe specific type ofmaterial featured in thedrawing. Should bemade with a 4H leadand light to moderatepressure. (However, theborders for the symbolbox are outlines—2Hlead.)

See Figure 10

FIGURE 9—Here areexamples of the types oflines used in an architecturaldrawing to represent actualedges of an object. Theoutline is used for specialemphasis. The object lines,on the other hand, representedges that aren’t part of theoutline of the roof. Also, notethe hidden object linerepresenting the edge of abrace that would be invisiblein this cutaway view.


Now, take a few moments to review what you’ve learned about thestandards for drafting lines by completing Learning Check 2.

FIGURE 10—This architecturaldrawing shows examples of a dimension line, anextension line, a centerline,and texture lines.


Learning Check 2Questions 1–5: Indicate whether each of the following statements is True or False.

_____ 1. A visible object line is a thin line.

_____ 2. Visible lines are unbroken lines.

_____ 3. In mechanical drafting, the dashes that form a hidden line should each be 1⁄32′′ long.

_____ 4. Centerlines are used only on round holes and round solids.

_____ 5. Texture lines should be drawn with light to moderate pressure.

Questions 6–15: Match the terms on the left with their descriptions on the right. Indicateyour choices in the spaces provided. All the lettered choices must be used.

_____ 6. Break lines

_____ 7. Section lines

_____ 8. Phantom lines

_____ 9. Cutting-plane lines

_____10. Stitch lines

_____11. Centerlines

_____12. Hidden lines

_____13. Dimension lines

_____14. Visible lines

_____15. Texture lines

a. Should be called out

b. May contain freehand zigzags

c. Indicate edges that can actually be seen

d. Have an arrowhead at each end

e. May end in slash marks on architectural drawings

f. Are also called invisible lines

g. Include spaces that are 1⁄16′′ long

h. Indicate an imaginary cutting surface

i. Can designate a part’s alternate position

j. Indicate the type of material used in the object or area

Check your answers with those on page 19.


1

1. 45

2. round

3. three

4. 7

5. architectural

6. rotate

7. gray

8. four

2

1. False. Visible object lines should be drawnwith at least a medium thickness.

2. True

3. False. The dashes should be 1⁄8′′ long; thespaces between the dashes should be 1⁄32′′long.

4. False. A centerline could be used to markan imaginary line that divides any shapesymmetrically.

5. True

6. b

7. h

8. i

9. d

10. a

11. g

12. f

13. e

14. c

15. j

Learning Check Answers

19

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