1. Dimension Terminology:

2. Avoid placing dimensions on the part (inside of the view)
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3. Avoid dimensioning to hidden features
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4. Always place dimensions where the characteristic shape is shown in the most descriptive view
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5. Always dimension holes in their circular view with the Ø
Always dimension holes in their circular view with the Ø. Specify special features (hole types) with a note.
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6. Dimension rounded corners and arc features as radii where they appear in their rounded view.
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7. Dimension cylinders in their rectangular view with a diameter symbol…
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8. Keep dimensions between views whenever possible
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9. Extension lines may cross each other and over other lines on the part, but dimension lines should never be crossed. (Hint no “arrow-headed” lines can cross “arrow-headed” lines)
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10. The overall dimension should always be given
The overall dimension should always be given. It should be placed outside of smaller dimensions and be the farthest from the part.
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11. Do not duplicate dimensions and avoid using unnecessary or superfluous dimensions
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12. When all of the dimensions are expressed as inches
When all of the dimensions are expressed as inches. DO NOT use inch marks ('') or the abbreviation (.in)
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13. For metric drawings, omit the use of the millimeter (mm) notation following the numeral, as millimeters are the default units.
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14. Extend leaders from the first or last word in a note
Extend leaders from the first or last word in a note. Point them toward (but not touch) the center of the circular features that they are specifying.
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15. Place dimensions among the various views to avoid crowding
Place dimensions among the various views to avoid crowding. Stagger horizontal dimensions to avoid contact or crowding of the values
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16. Chamfers:
Break away sharp edges and help guide the part into a mating assembly. May be specified with one distance and one angle, or with two distances.

17. Necks: Necks are used for “O” ring seals, parts turned on lathes,
and designed failure points

18. Knurls:
Knurling is a process of rolling patterns onto cylindrical objects to make them easier to grip.

19. Dimensioning in small places

20. Repetitive features A combination of
dimensioning & notes is used. A number in parenthesis indicates how many are required. The word TYPICAL (or TYP) indicates that all shown are the same.