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CHAPTER 6

CHAPTER 6. Lines and Lettering. Learning Objectives. Identify the lines found on a given industry drawing Draw ASME standard lines Solve engineering given problems Create ASME standard text Answer questions related to lines and lettering. Lines. Must be of a quality that reproduces easily

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CHAPTER 6

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  1. CHAPTER 6 Lines and Lettering

  2. Learning Objectives • Identify the lines found on a given industry drawing • Draw ASME standard lines • Solve engineering given problems • Create ASME standard text • Answer questions related to lines and lettering

  3. Lines • Must be of a quality that reproduces easily • Dark, crisp, sharp, and of the correct thickness • No variation in darkness • Variation in thickness • Thicker lines stand out clearly • Thinner lines are subordinate

  4. Mechanical Drafting Line Standards • ASME Y14.2, Line Conventions and Lettering • Thick lines .02 in. (0.6 mm) • Twice as wide as thin lines • Thin lines .01 in. (0.3 mm) • Half as as wide as thick lines • Military (MIL) standards (STD) • Thick • Medium • Thin

  5. ASME Line Conventions

  6. ASME Example [Insert Figure 6.2]

  7. Construction Lines • Layout • Do not represent a specific drawing feature • Not reproduced on the final drawing

  8. Visible Lines • Object lines, or outlines • Visible surfaces or edges • Continuous (solid) • Thick • .02 in. (0.6 mm) • ASME example

  9. Hidden Lines • Invisible edges • 125 in. (3 mm) dashes spaced .06 in. (1.5 mm) apart • Thin • .01 in. (0.3 mm) • ASME example

  10. Hidden Line Rules

  11. Centerlines • Centers of circles and arcs • Center axis of a circular or symmetrical form • Centers in a bolt circle pattern • Paths of motion in a mechanism

  12. Centerlines • Series of alternating long and short dashes • Long dash .75 to 1.50 in. (19-35 mm) • Spaces between dashes .062 in. (1.5 mm) • Short dash .125 in. (3 mm)

  13. Centerlines • Extend .125 in. (3 mm) or .25 in. (6 mm) past objects • Thin • .01 in. (0.3 mm) • ASME example

  14. Bolt Circle • Polar coordinate dimensions • Rectangular coordinate dimensioning

  15. Symmetry

  16. Extension Lines • Establish the extent of a dimension • Begin with a .06 in. (1.5 mm) space from the object • Extend .125 in. (3 mm) beyond the last dimension • Thin • .01 in. (0.3 mm) • ASME example

  17. Extension Line Rules • Can cross object lines, centerlines, hidden lines, other extension lines • Should not cross dimension lines • Centerlines become extension lines for dimensioning purposes

  18. Dimension Lines • Capped on the ends with arrowheads • Broken to provide a space to indicate the length of the dimension • Thin • .01 in. (0.3 mm) • ASME example

  19. Leader Lines • Leaders • Connect a specific note to a feature • Direct dimensions • Symbols • Item numbers • Part numbers

  20. Leader Lines • 45°, 30°, or 60° angles common • .125 to .25 in. (3-6 mm) shoulder common • Pointing to a line: cap with an arrow • Pointing to a dimension line: no arrow • Pointing inside an object: cap with a .05 in. (1.5 mm) dot

  21. Leader Lines • Continuous or hidden • Thin • .01 in. (0.3 mm) • ASME example

  22. Leader Line Rules • Not cross each other • Not excessively long • Not parallel to dimension lines, extension lines, or section lines • Avoid 75°or less than 15°angles from horizontal

  23. Arrowheads • Terminate dimension lines and leader lines • Cutting plane lines and viewing plane lines • Twice as big as arrowheads on dimension and leader lines • Three times as long as wide • .125 in. (3 mm) long for dimension lines and leader lines • Consistent sizes • Open or filled • ASME example

  24. Cutting-Plane and Viewing-Plane Lines • Thick • .02 in. (0.6 mm) • Takes precedence over the centerline • ASME example

  25. Cutting-Plane and Viewing-Plane Lines

  26. Section Lines • Appear in the view of a section • Show where the cutting-plane line cuts through material • 45°, 30°, or 60°angles common • Thin • .01 in. (0.3 mm) • ASME example

  27. Section Line Rules • Equally spaced • ASME minimum space .06 in. (1.5 mm) • Avoid 75°or less than 15°angles from horizontal • Not parallel or perpendicular to object lines • Opposite directions on adjacent parts • Thin parts can be shown without section lining • Omit around text when necessary to have text in a sectional view

  28. Section Lines • Outline section lining • Coded section lines • Thin parts shown without section lining

  29. Short Break Lines • Shorten the length of a long object or part • Provide a partial view of a feature • Thick • .02 in. (0.6 mm) • ASME example

  30. Long Break Lines • Break long distances • Thin • .01 in. (0.3 mm)

  31. Phantom Lines • Alternate positions of moving parts • Adjacent positions of related parts • Repetitive details • Contour of filleted and rounded corners • Thin • .01 in. (0.3 mm) • ASME example

  32. Chain Lines • Indicate specified treatment • Projected tolerance zone • Alternately spaced long and short dashes • Thick • .02 in. (0.6 mm) • ASME example

  33. Stitch Lines • Indicate the location of stitching or sewing • Short thin dashes, or • .01 in. (0.3 mm) diameter dots spaced .12 in. (3 mm) apart

  34. Lettering • Dimensions • Notes • Titles

  35. Lettering • Must be of a quality that reproduces easily • Dark, crisp, sharp • CADD text • Font

  36. ASME Lettering Standards • ASME Y14.2, Line Conventions and Lettering • Opaque • Clearly spaced • Vertical or inclined • One style • Upper case letters

  37. Lettering on Engineering Drawings • Single-stroke Gothic • Vertical uppercase letters • Arial, Century Gothic, RomanS, or SansSerif font

  38. Lettering Numbers

  39. Inclined and Lowercase Lettering Styles • Inclined • 68°to the right from horizontal • Structural drafting • Civil drafting or maps • Lowercase • Uncommon in mechanical drafting • Engineering specifications • Civil drafting or maps

  40. Architectural Lettering • Traditional freehand architectural lettering with an artistic flair • StylusBT, ArchiText, CountryBlueprint, or CityBlueprint fonts • United States National CAD Standard (NCS) • SansSerif font

  41. Lettering Legibility • Background area between letters: • Approximately equal • Individual words clearly separated • Space between two numerals with a decimal point between: • Minimum two-thirds the lettering height • Vertical space between lines of lettering • No more than the lettering height, no less than half the lettering height

  42. ASME Letter Heights

  43. Lettering Notes

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