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ADVANCED MECHANICAL DRAFTING

ADVANCED MECHANICAL DRAFTING. LECTURE #5. PREPARING TO DRAW MANUALLY. Purchase MECHANICAL vellum – size B, C, or D Use proper line types Use proper line weights Object lines thick Hidden lines medium Center, phantom, & dimension lines thin Borders, cutting plane lines very thick

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ADVANCED MECHANICAL DRAFTING

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  1. ADVANCED MECHANICAL DRAFTING LECTURE #5

  2. PREPARING TO DRAW MANUALLY • Purchase MECHANICAL vellum – size B, C, or D • Use proper line types • Use proper line weights • Object lines thick • Hidden lines medium • Center, phantom, & dimension lines thin • Borders, cutting plane lines very thick • Construction very thin and light • Use proper text size • Notes, dimensions, labels 1/8” • Drawing title and project 3/16” • Use proper dimensioning techniques – review lecture #2 and DT-1000 student packet

  3. PREPARING TO DRAW IN AUTOCAD • Load drawing format – size B, C, or D • Move border and title block lines and text to appropriate layers • Create layers and define line weights and colors • Define dimension defaults • Define text font and size • Save format under a new name for later drawings if necessary

  4. LAYER DEFINITION REQUIRED LAYERS: Border1 Cutting plane Object Border 2 Dimension Phantom Centerline Hidden Text Add other layers if desired DO NOT DEFINE OR CHANGE THE COLOR, WEIGHT, OR TYPE OF ANY INDIVIDUAL ENTITY. DRAW EACH ON ITS APPROPRIATE LAYER

  5. SETTING DIMENSION STYLES MENU PICKS: Dimension Style . . . Modify . . .

  6. GEAR SHIFT HANDLE (GSH)

  7. OVERVIEW • B-size drawing • Manual – vellum with mechanical title block • CAD – format found in c:\title blocks\mech • One view required since “Ø” symbol will be used on cylindrical parts • Longitudinal centerline required • Enlarged detail of retaining ring grooves required • Design part in English units (inches), them convert to metrics (millimeters) for detailing

  8. DEM 3-9-03 Revision block to be discussed later Project – always “TWO-SPEED TRANSMISSION” Title – part name from layout Drawing number – found with part name on layout Scale – “FULL” for all drawings Revision – begins at “0” and updates when drawing is revised Drawn By – your last name Date Drawn – date you finish the drawing Layout – always “100” - found on design layout Checked By and Date Checked are filled in by the checker (me) after the drawing is turned in. You place them on the drawing when you revise it. Weber School District ANDERSEN 3-9-03 TWO-SPEED TRANSMISSION 100 GEAR SHIFT HANDLE 103 0 FULL

  9. Title Block Tolerances apply to all dimensions without specified limits or tolerances Third Angle Projection symbol specifies the projection standard used on the drawing Species that ANSI standards are applied to all parts of the drawing STANDARD TITLE BLOCK DATA Weber

  10. GENERAL NOTES RULES • Must be clear, accurate, complete, and capable of only one interpretation • Use only commonly understood trade terms • Must be simple, brief, and concise • Use a condensed form, like a telegraph • Use only commonly understood abbreviations • Instructional notes should be in present tense • When the same note is used on multiple drawings, its wording should be identical on each one • Should never repeat information found elsewhere on the drawing • Should not refer to information on other drawings or documents, but if the need arises, no reference should be made to data from more than one drawing or back • Should always be placed horizontally on the drawing • Notes that apply to a specific feature on a detail drawing or to a specific part on a layout should be placed adjacent to that item • Should not be underlined (except section labels)

  11. INCHES or MILLIMETERS GENERAL NOTES General notes shall be placed at the bottom of the drawing next to the title block and shall be placed so as to allow empty space all around GENERAL NOTES: • REMOVE ALL BURRS AND BREAK ALL SHARP EDGES. • UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE IN __________. Standard General Notes for Machined Parts: GSSP, GSH, GSK, DG, DS Other notes may be added later

  12. ENGLISH TO METRIC CONVERSION(INCHES TO MILLIMETERS) • Conversion factor  1” = 25.4 mm • Round off to one fewer decimal place than English • Zero precedes decimal point for dimensions < 1 mm • Angles specified in decimal degrees • Round upper limits down and lower limits up so as not to exceed original envelope of tolerance • Round “MAX” dimensions down and “MIN” dimensions up similar to limits • Remember to convert all dimensions on the drawing, including those in notes, callouts, and title block

  13. EXAMPLES: .562  14.2748  14.27 3.38  85.852  85.9 .0047  .11938  .119  0.119 .001  .0254  .03  0.03 .005 MAX  .127  .12  0.12 MAX .012 MIN  .3048  .31  0.31 MIN 2.561 2.554 65.0494 64.8716 .0036 .0033 0.091 0.084 .091 .084 65.04 64.88 .09144 .08382    HANDLE DESIGN ALL DIMENSIONS ON THE HANDLE (GSH) MUST BE DESIGNED IN ENGLISH AND DRAWN IN METRICS • STEPS: • Determine the proper English dimension (inches) • Multiply the English dimension by 25.4 • Round the metric dimension to one decimal place less than the English • If dimension is a limit, round upper limit down and lower limit up • Round “MAX” dimensions down, round “MIN” dimensions up • Add leading zeros to any dimension < 1 millimeter

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