BOARD DRAFTING - MECHANICAL PURPOSE To evaluate each contestant's preparation for employment and to recognize outstanding students for excellence and professionalism in the field of machine drafting. First, refer to General Regulations. CLOTHING REQUIREMENT SkillsUSA-VICA Blazer, sweater, or windbreaker and accompanying official dress. Or appropriate professional/business attire. ELIGIBILITY Open to active SkillsUSA-VICA members enrolled in programs with machine drafting as the occupational objective. EQUIPMENT AND MATERIALS 1. Supplied by the technical committee: a. A drafting table with a T-square b. Drafting paper c. Reproduction equipment d. Technical pens, ink and supplies e. All necessary information and furnishings for judges and technical committee 2. Supplied by the contestant: a. Drawing instruments b. 30-60-degree triangle, 45-degree triangle, and/or adjustable triangle c. Mechanical engineering scale d. Machinery's Handbook (Industrial Press) e. Erasers and erasing shields f. Drafting tape g. Appropriate pencils and/or lead holders and leads h. Sanding board or pencil and/or lead pointers i. French curves j. Dusting brush k. Standard machine drafting templates
l. Dusting bag or powder m. Pocket calculator n. Other personal drafting supplies desired for machine drafting subject to the approval of the technical committee 3. Contestants may not bring their own: a. Drafting machines b. Parallel rule devices c. Erasing machines(cord or cordless) d. Lettering templates or lettering sets SCOPE OF CONTEST 1. Contestants will demonstrate their ability to perform jobs or skills selected from the following list of competencies. a. Scale Usage 1. Read the mechanical engineers scale 2. Read the metric scale b. Sketching 1. Prepare proportional design sketches 2. Make freehand sketch 3. Sketch oblique views 4. Sketch isometric pictorial views 5. Construct oblique views 6. Draw various perspective views c. Orthographic Views and Geometric Constructions 1. Construct various geometric forms using instruments 2. Construct various orthographic views in third angle projection 3. Construct various orthographic views in first angle projection 4. Construct isometric pictorial views 5. Construct oblique views 6. Draw various perspective views d. Basic Tolerancing 1. Interpret decimal tolerance dimensions 2. Calculate and assign tolerances to mating parts using standard fit tables 3. Construct a drawing using datum dimensioning e. Inking Tools and Techniques 1. Draw and erase ink lines on vellum or tracing cloth 2. Draw and erase ink lines on polyester film 3. Complete steps in inking a drawing or a tracing 4. Fill clean technical and pocket model pens
f. Auxiliary Views 1. Label points and planes of a three view drawing 2. Construct a primary auxiliary of an inclined plane 3. Construct a true size auxiliary of a curved surface 4. Construct true length of an oblique line 5. Determine the true angle and slope of a line 6. Determine the true angle between two planes 7. Determine visibility of crossing skew lines in space 8. Determine the visibility of a line and a plane that cross in space 9. Locate piercing point of a line and plane 10. Construct a secondary auxiliary view of an object 11. Construct point view of a line 12. Determine true angle between two planes in a secondary auxiliary 13. Construct a true size auxiliary of an oblique plane 14. Determine shortest distance between a point and a line 15. Determine shortest distance between two skew lines Sectional Views 1. Construct various material symbols in section 2. Construct a full section of an object 3. Construct a half-section of an object 4. Construct an offset section of an object 5. Construct a broken-out section of an object 6. Construct a removed section of an object 7. Construct a revolved section of an object 8. Construct a rib section of an object 9. Construct an aligned section of an object with holes, ribs or spokes 10. Construct adjacent parts in assembly section 11. Construct conventional breaks 12. Construct an assembly section h. Tools and Equipment 1. Read micrometer settings 2. Read venier calipers 3. Measure with scales 4. Compute mechanical drafting problems using a hand calculator 5. Use a micrometer 6. Use a venier caliper
i. Reference Materials 1. Determine manufacturer of mechanical components from Thomas Register 2. Write a letter requesting product literature for mechanical components 3. Write a technical report using reference materials j. Layouts and Working Drawings 1. Draw a design layout 2. Draw a set of detail drawings 3. Draw an assembly drawing 4. Complete a detailed title block and revision block 5. Complete a parts list 6. Make a drawing revision k. Dimensioning and Tolerancing 1. Dimension an object completely 2. Calculate and dimension clearance fit tolerances using standard fit tables 3. Calculate and dimension interference fit tolerances using standard fit tables 4. Calculate and dimension interference fit tolerances to mating parts using standard fit tables 5. Calculate and dimension hole size limits for standard dowels 6. Dimension an object using position and form tolerances 7. Determine ranges of motion of limbs and spaces required for a person l. Fasteners and Hardware 1. Construct thread symbols 2. Construct bolts, screws and nuts 3. Construct an assembly containing various fasteners 4. Construct a welded assembly drawing 5. Construct spring drawings to include specifications 6. Construct keys in assembled positions 7. Write specifications for hardware from vendor catalogues
m. Presentation Drawings 1. Shade pictorials 2. Construct an oblique presentation drawing 3. Construct a two-point presentation perspective of an object 4. Construct an exploded assembly presentation drawing n. Materials and Specifications 1. Determine wire and sheet metal size from gage number 2. Select materials from a materials stock book o. Manufacturing Processes 1. Calculate bend allowance for sheet metal 2. Design a casting part 3. Design a forging part 4. Design a welded part 5. Design a thermoplastic part p. Sheet Metal Developments 1. Label points, lines, and planes in views 2. Identify true lengths and types of lines 3. Identify true sizes and types of planes 4. Construct lengths of lines and true sizes of planes using auxiliary views 5. Construct true lengths of lines by rotation 6. Construct true sizes of planes by rotation 7. Locate elements of single curved surfaces 8. Construct intersections of surfaces 9. Construct intersections 10. Construct radial line developments 11. Construct parallel line developments 12. Construct special development using triangulation q. Power Transmission 1. Construction a spur gear drawing 2. Construct a bevel gear 3. Construct a worm and worm gear 4. Calculate gear ratios 5. Determine gear rotation 6. Calculate gear speeds 7. Construct a cam drawing 8. Select a chain drive
9. Select a V-Belt drive 10. Select types of bearings from handbooks 2. Preparation of drawings will include proper scaling and tolerancing. 3. Rating of problems will be done from reproduced copy, however, judges will observe the entire contest. 4. All lettering will be freehand. Drafting media may consist of paper, mylar (polyester film) or sepia. 5. Finished work will be done with ink or pencil on appropriate material as directed by the technical committee. 6. Time limit will be four to five hours as determined by the technical committee.
BOARD DRAFTING - MECHANICAL RATING FORM ITEM PTS Correct solution to problem 50 CONTESTANT NUMBER Line work 25 Lettering 15 Reproducibility 15 Layout and balance 15 Neatness 20 Accuracy 50 Dimensions 35 Written test 25 SUBTOTAL 250 CLOTHING PENALTY 0 TO -12 TOTAL