Dimensioning of Engineering Drawings

1. Dimensioning ofEngineering Drawings TEC 315 Dr. Lou Reifschneider Dave Myszka material from: www.engr.udayton.edu/faculty/dmyszka/WebPages/mct111L/Dimen.pdf

2. Engineering Drawing • A document that communicates a precise description of a part. • A legal document: must be formal and precise. • Drawings are the blueprint that drive manufacturing of the product. • Dimensions and Tolerances are critical components of all engineering drawings.

3. Types of Dimensions • Linear - typically decimal inches. • Angular - sized in degrees. • Reference • not to be used for machining or layout. • Examples (1.250) or 1.250 REF • Tabular • useful when a series of designs follow the same pattern • useful for hole charts to facilitate machining set-up • Arrowless dimensioning (less clutter) • Dual dimensioning - english and [metric]

4. Datum Dimensioning Avoids Tolerance Stacking If all dimensions were +/-.001, what would the position of corner A be from corner B if datum dimensioning was not used? ________ A B Print Reading for Industry, Brown & Brown, Fig. 12-11

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6. Reference dimensions help clarify design intent, but should not used to layout machining. They are redundant dimensions. Print Reading for Industry, Brown & Brown, Fig. 12-2

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8. A feature should be dimensioned in a view that is most descriptive of its shape. Print Reading for Industry, Brown & Brown, Fig. 12-7

9. Print Reading for Industry, Brown & Brown, Fig. 12-7

10. Print Reading for Industry, Brown & Brown, Fig. 12-7

11. A feature should be dimensioned in a view that is most descriptive of its shape. Print Reading for Industry, Brown & Brown, Fig. 12-7

12. Dimension External Cylindrical Shapes from Rectangular View Print Reading for Industry, Brown & Brown, Fig. 12-8 Dave Myszka

13. Convention for Counter bored Hole Print Reading for Industry, Brown & Brown, Fig. 14-2

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20. Tabular dimensions simplify drawings of family parts. Print Reading for Industry, Brown & Brown, Fig. 12-3

21. Hole charts facilitate machining set-up Print Reading for Industry, Brown & Brown, Fig. 12-4

22. Arrowless Dimensioning(for greater clarity) Print Reading for Industry, Brown & Brown, Fig. 12-5

23. Dimensioning Practice in Class Announcements?