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Standard Engineering Letteringand Lines

Elements of Engineering DrawingEngineering drawing are made up of graphics language and word language.

Elements of Engineering DrawingGraphicslanguageWordlanguageEngineering Drawing

Introduction to Types of LinesEach line has a definite form and line weight.

The standard thick line weight is 0.6mm HB Lead.

The standard thin line weight is 0.3mm HB Lead.

The standard construction line weight is 0.5mm 2H Lead.

Basic Line Types &Name according to applicationContinuousDashChainStyleThicknessThickThin1. Dimension line2. Extension line3. Leader lineCenter lineHidden lineVisible linerepresent features that can be seen in the current view.represent features that cannot be seen in the current view.represents symmetry, path of motion, centers of circles,axis of axisymmetrical parts.indicate the sizes and location of features.1. Visible line3. Hidden line4. Center line2. Dimension line Extension line Leader line

Main Line TypesLinesHidden LinesCenter LinesDimension LinesExtension LinesLeader LinesCutting PlanesSection LinesPhantom LinesViewing PlanesBreak LinesVisible Lines

Visible/Object LinesDark, heavy lines.Used to represent the outline or contour of the object being drawn.Define features you can see in a particular view.

Hidden LinesLight, narrow, short, dashed lines.Shows the outline of a feature that can not be seen in a particular view.Used to help clarify a feature, but can be omitted if they clutter a drawing.

Hidden Lines (Technique)

Section LinesThin line usually drawn at a 45 degree angle.Indicates the material that has been cut through in a sectional view.

Center LinesThin line consisting of alternating long and short dashes.Used to represent the center of round or cylindrical features, or the symmetry of a feature.

Dimension LinesThin lines capped on the ends with arrowheads and broken along their length to provide a space for the dimension numeral.They indicate length.

Extension LinesThin lines used to establish the extent of a dimension.Can also be used to show extension of a surface to a theoretical intersection as shown in (b).Begin 1.5mm from the object and extend to 3mm beyond the last dimension.They should not cross dimension lines.

Leader LinesThin lines used to connect a specific note to a feature.Also used to direct dimensions, symbols, item number and part numbers on a drawing.Commonly drawn at 45, 30 and 60 degrees.Has a short shoulder (3-6mm) at one end beginning at the center of the vertical height of text, and a standard dimension arrowhead at the other end touching the feature.Leader lines should not cross each other.Leader lines should not be excessively long.Leader lines should not be vertical or horizontal.Leader lines should not be parallel to dimension lines, extension lines or section lines.

ArrowheadsUsed to terminate dimension lines and leader lines and on cutting-plane lines and viewing plane lines.They should be three times as long as they are wide.They should be the same size throughout the drawing.The filled arrowhead is generally preferred because of its clarity.

Cutting Plane LinesThick broken line that is terminated with short 90 degree arrowheads.Shows where a part is mentally cut in half to better see the interior detail.

Cutting Plane Lines (Example)

Break LinesUsed to break out sections for clarity or for shortening a part.

Three types of break lines with different line weights:

Short Breaks.Long Breaks.Cylindrical Breaks.

a) Short Break LinesThick wavy line.Used to break the edge or surface of a part for clarity of a hidden surface.Short break line on metal shape; Short Break Line on wood shape.

b) Long Break LinesLong, thin lines.Used to show that the middle section of an object has been removed so it can be drawn on a smaller piece of paper.

c) Cylindrical Break LinesThin lines.Used to show round parts that are broken in half to better clarify the print or to reduce the length of the object.Cylindrical conventional breaks for a solid and tube; where R = Radius

Phantom LinesThin lines made up of long dashes alternating with pairs of short dashes.

Three purposes in drawingsTo show the alternate position of moving parts.To show the relationship of parts that fit together.To show repeated detail.

Phantom Lines (Examples)

Grades of Pencils used in Lines

Example 1

Example 2

Lettering in Engineering DrawingLettering is used to provide easy to read and understand information to supplement a drawing in the form of notes and annotations.Thus, it must be written with:Legibility shape & space between letters and words.Uniformity size & line thickness.Lettering is an essential element in both traditional drawing and Computer Aided Design (CAD) drawing

Types of LetteringThe two types of lettering are:Double Stroke Lettering.Single Stroke Lettering.

1. Double Stroke LetteringIn Double Stroke Lettering the line width is greater than that of Single Stroke Lettering.

Double Stroke Lettering is further divided into:Double Stroke Vertical Gothic Lettering.Double Stroke Inclined Gothic Lettering.

A stencil is mostly used when hand drawing double stroked letters.

2. Single Stroke LetteringThickness in single stroke lettering is obtained by a single stroke of pencil or ink pen.It is further divided into: (a) Single Stroke Vertical Gothic Lettering.(b) Single Stroke Inclined Gothic Lettering.Single stroke vertical lettersSingle stroke inclined letters

Conventions for LetteringUse all CAPITAL LETTERS.Use even pressure to draw precise, clean lines.Use one stroke per line.Horizontal Stroke are drawn left to right.Vertical Strokes are drawn downward.Curved strokes are drawn top to bottom in one continuous stroke on each side.Use kerning to eliminate excessive space between letters. [kerning refers to adjusting the space between characters, especially by placing two characters closer together than normal. Kerning makes certain combinations of letters, such as WA, MW, TA, and VA, look better.]

Conventions for Lettering (cont.)Use The Single-stroke, Gothic Style of Lettering.Always Skip A Space Between Rows Of Letters.Always Use Very Light Guide Lines.Fractions Are Lettered Twice The Height Of Normal Letters.Fraction Bars Are Always Drawn Horizontal.Use a Medium (B, HB, F or H) Lead For Normal Lettering.Use a Hard (2H To 4H) Lead For Drawing Guide Lines.Notes should be double spaced.

Application of LetteringLettering in Engineering Drawings is used in writing Title Blocks which play a crucial role in drawings, they are used to record all of the important information necessary for the working drawings. A HB Pencil is used. What does the Title Block contain? Other uses of lettering include Dimensions and Notes on the engineering drawing.

Placement of text on Engineering Drawings Try and locate the text on the drawings going around.

GuidelinesExtremely light horizontal lines that are necessary to regulate the height of letters.

In addition, light vertical or inclined guidelines are needed to keep the letters uniformly vertical or inclined.

Guidelines are absolutely essential for good lettering.

Guidelines are drawn using Hard (2H to 4H) Lead Pencils with light pressure. HB grade conical end pencils are used for lettering.Procedure for Lettering Thin horizontal guide lines are drawn first at a distance h apart.Lettering Technique: Horizontal lines of the letters are drawn from left to right. Vertical, inclined and curved lines are drawn from top to bottom.After lettering has been completed, the guidelines are not erased.

Guidelines in Lettering (including Height) hc1 c2 c3 b1 b2 -(height of capital letters)-(height of lower-case letters)-(tail of lower-case letters) -(stem of lower-case letters)-(spacing between baselines)-(spacing between baselines) hc2c2

Recommended Size (height, h) of Letters/NumeralsMain Title5mm, 7mm, 10mmSub-Title3.5mm, 5mmDimensions, Notes etc.2.5mm, 3.5mm, 5mm

Guidelines for LetteringDrawing numbers, title blocks and letters denoting cutting planes, sections are written in 10mm size.Drawing title is written in 7mm size.Hatching, subtitles, materials, dimensions, notes etc. are written in 3.5 mm size.Space between lines is 3/10 h (height of capital letters)Space between words may be equal to the width of the alphabet M or 3/5 h (height of capital letters). Standard height for CAPITAL Letters and Numerals according to the Bureau of Indian Standards (BIS) is: 1.8, 2.5, 3.5, 5, 6, 10, 14, 20 mm. (Sizes selected based upon size of drawing)

Guidelines for Lettering

Basics of Single StrokingStraightSlantedCurvedHorizontal1123I letterA letter123456B letterExamples

Order of StrokesStroking is done based on the slope of each letter and the strokes vary with order and direction.

Various Single StrokingGroups

Stroking for Upper Case Letters & NumeralsStraight linelettersCurved lineletters&Numerals

Stroking for Lower Case Letters

Stroking GroupsThe I-H-T GroupThe letter I is The Foundation Stroke.The top of T is drawn first to the full width of the square and the stem is started accurately at its mid point.IHT

Stroking GroupsThe L-E-F GroupThe L is made in two strokes.The first two strokes of the E are the same for the L, the third or the upper stoke is lightly shorter than the lower and the last stroke is the third as long as the lower.F has the same proportion as E.LEF

Stroking GroupsThe V-A-K GroupV is the same width as A, the A bridge is one third up from the bottom.The second stroke of K strikes stem one third up from the bottom and the third stroke branches from it.VAK

Stroking GroupsThe M-W GroupAre the widest letters.M may be made in consecutive strokes of the two verticals as of N.W is made with two Vs.MW

Stroking GroupsThe O-Q-C-G GroupThe O families are made as full circles and made in two strokes with the left side a longer arc than the right.A large size C and G can be made more accurately with an extra stroke at the top.OQCG The O-Q-C-G Group stroking will be demonstrated on the whiteboard

Stroking GroupsThe O-Q-C-G Group (cont.)

Stroking GroupsThe D-U-J GroupThe top and bottom stokes of D must be horizontal, fail line to observe this is a common fault with beginnersU is formed by two parallel strokes to which the bottom stroke be added.J has the same construction as U, with the first stroke omitted.DUJNote:- The bottom stroke in J is drawn once, and not twice as shown in the animation.

Stroking GroupsThe P-R-B GroupThe number of stokes depends up on the size of the letter.The middle line of P and R are on centerline of the vertical line.PRB

Stroking GroupsThe N-Z-X-Y GroupThe parallel sides of N are generally drawn first. Z is drawn without lifting the pen. Z and X are both started inside the width of the square on top and run to full width on the bottom. NZXY

Other Stroking GroupsThe S-8-3 Group The 0-6-9 Group A perfect 3 should be able to be completed into an 8; An 8 can be made from an S construction. The S is made up of three strokes. The cipher (zero) is narrower than the letter O and made of two strokes. The 6 and 9 have the cipher as their backbone. With their lobes 2/3 the figures height.

Other Stroking Groups The 2-5-7-& Group The Fraction Group Always made with a horizontal vinculum (a horizontal line used in mathematical notation).The figures are two-thirds the height of the whole numbers, with a clear space above and below the line, making the total height of the fraction nearly twice the cap height (h). The bottom of 2 and top of 5 and 7 should be straight lines. For 2 the reverse curve should cross the center of the space. The ampersand (&) is made of three strokes.

The Fraction Group (Example)

Sample Video(showing single stoking in lettering)

Spacing Uniformity in spacing of letters is a matter of equalizingspaces by eye. The background area between letters, not the distance between them, should be approximately equal. Words are spaced well apart, but letters within words should be spaced closely.

For either upper case or lower-case lettering, make the spaces between words approximately equal to a capital O.

Avoid spacing letters too far apart and words too close together.LINESANDLETTERINGSLINESTTERSEL

Types of Spacing

Space between lettersContour can be denoted as straight, slant and curve.Adjacent contour can be1. straight-straight : II, IN, IM, IP etc.2. straight-curve (or curve-straight) : IO, QR etc.3. straight-slant (or slant-straight) : IV, IW etc.4. curve-curve : OO, OG etc.5. slant-curve (or curve-slant) : VO, WG, VC etc.6. slant-slant : VW, VX etc.7. The L and T : LT

Space between letters

Space between letters

Lettering Uniformity Important to produce good drawings.Uniform in style, size, inclination, weight and space.Carelessness might result in mistakes.ENGINEERING DRAWINGSSpace between letters Spacing between characters, is normally (2/10)h.Spacing between words, is normally (6/10)h.where h is the cap height.

Examples of Common Mistakes in LetteringL E t T E r I N GL E T T E R I N GL E T T E R I N GLET T E R INGL E T T E R I N GLettering style not uniformLettering height not uniformLettering inclination not uniformLettering thickness not uniform Lettering space not uniform

ReferencesFrench, T. E., (1918). A MANUAL OF ENGINEERING DRAWING FOR STUDENTS AND DRAFTSMEN. London: Hill Publishing Co., Ltd.Engineering Drawing Fundamentals: Introduction to Engineering Drawing. Retrieved from http://pioneer.netserv.chula.ac.th/~kjirapon/lecture-note.html.Madsen D. A., Madsen D. P., (2011). ENGINEERING DRAWING & DESIGN, Fifth Edition. New York: Cengage Learning.Reddy K. V., (2008). TEXTBOOK OF ENGINEERING DRAWING. Hyderabad: BS Publications.

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