advanced mechanical drafting
DESCRIPTION
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 linesthick Hidden linesmedium Center, phantom, & dimensionlinesthin Borders, cutting plane linesvery thick - PowerPoint PPT PresentationTRANSCRIPT
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
– 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
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
LAYER DEFINITION
REQUIRED LAYERS:Border1 Cutting plane ObjectBorder 2 Dimension PhantomCenterline 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
SETTING DIMENSION STYLES
MENU PICKS:
Dimension
Style . . .
Modify . . .
GEAR SHIFT HANDLE (GSH)GEAR SHIFT HANDLE (GSH)
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
TWO-SPEED TRANSMISSION
GEAR SHIFT HANDLE
1030FULL
ANDERSEN3-9-03DEM
3-9-03
100
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
Title Block Tolerances apply to all dimensions without specified limits or tolerances
STANDARD TITLE BLOCK DATA
Third Angle Projection symbol specifies the projection standard used on the drawing
Species that ANSI standards are applied to all parts of the drawing
Weber
GENERAL NOTESRULES
1. Must be clear, accurate, complete, and capable of only one interpretation
2. Use only commonly understood trade terms3. Must be simple, brief, and concise4. Use a condensed form, like a telegraph5. Use only commonly understood abbreviations6. Instructional notes should be in present tense7. When the same note is used on multiple drawings, its wording
should be identical on each one8. Should never repeat information found elsewhere on the drawing9. 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
10. Should always be placed horizontally on the drawing11. 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 item12. Should not be underlined (except section labels)
GENERAL NOTES
GENERAL NOTES:
1. REMOVE ALL BURRS AND BREAK ALL SHARP EDGES.
2. UNLESS OTHERWISE SPECIFIED, ALL DIMENSIONS ARE IN __________.
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
Standard General Notes for Machined Parts:
GSSP, GSH, GSK, DG, DS
Other notes may be added later
INCHES or MILLIMETERS
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
HANDLE DESIGNALL DIMENSIONS ON THE HANDLE (GSH)(GSH) MUST BE DESIGNED
IN ENGLISH AND DRAWN IN METRICSSTEPS:
1. Determine the proper English dimension (inches)
2. Multiply the English dimension by 25.4
3. Round the metric dimension to one decimal place less than the English
1. If dimension is a limit, round upper limit down and lower limit up
2. Round “MAX” dimensions down, round “MIN” dimensions up
4. Add leading zeros to any dimension < 1 millimeter
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
2.5612.554
65.049464.8716
65.0464.88
.0036
.00330.0910.084
.091
.084.09144.08382