Monday, February 28, 2011

Dimension Notes

  • ANSI standards
    • no arbitrary
    • standard way of positioning dimensions, why?
    • describe size
    • locate details
Basic Rules
  • For convienence for manufactor
  • No calculations necessary
  • no duplications
Dim line
  • 1st 3/8 of an in. (9mm) from the object line should be
  • lines and symbols inside extension lines if possible
Extension lines
  • Extend from object but 1/16 inch (2mm) gap between object and extension line
Leaders
  • Scale=Dim. scale
  • runon angle so obvious not part of drawing
  • 1/4 inch tail
  • arrow if to edge, dot if to surface
  • crosss few lines
  • any<except horizontal or vertical
  • don't pass through corners
Linear
  • First big 3 H,W,D
  • in between viewws if possible
  • off view where detail is best described
  • do not dim from a hidden line
  • locate from common corner
  • smallest dim closest to object
  • no calc.
  • no duplications
Angle dim
  • Draw at same angle as object being dim
  • use degree symbol %%D
Circular
  • ARC-anything less then full circle dimas radius
  • circle always diam %%C
Circular objects
  • Cylinder-in profile (side) view
  • hole-where it shows as a hole

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