Adding Geometric Tolerances

Geometric tolerancing shows deviations of form, profile, orientation, location, and runout of a feature. You add geometric tolerances in feature control frames. These frames contain all the tolerance information for a single dimension. You can copy, move, erase, scale, and rotate feature control frames. You can snap to them using the object snap modes. You can use DDEDIT to edit feature control frames, or you can edit them with grips.

A feature control frame consists of at least two compartments. The first contains a geometric characteristic symbol that represents the geometric characteristic to which a tolerance is being applied, for example, form, orientation, or runout. Form tolerances control straightness, flatness, circularity, cylindricity, and profiles of line and surface. In the illustration, the characteristic is position.
The second compartment contains the tolerance value. Where applicable, the tolerance value is preceded by a diameter symbol and followed by a material condition symbol.

To add geometric tolerances

  1. From the Dimension menu, choose Tolerance.
  2. In the Geometric Tolerance dialog box, enter the tolerance values and modifying symbols.
    • Under Sym, click the first or second box to select a symbol for the first or second tolerance symbol, and then choose the symbol you want displayed in the Symbol dialog box.
    • Under Tolerance 1, select Dia to insert a diameter symbol.
    • Under Value, enter the first tolerance value.
    • Choose MC to add a material condition.
    • In the Material Condition dialog box, double-click a material condition symbol to insert it.
    • Add a second tolerance value (optional) in the same way as the first tolerance value.
    • Now add the datum reference letters and their modifying symbols (optional).
  3. Choose OK.

To add datum reference letters

  1. In the Geometric Tolerance dialog box under Datum 1, enter the primary datum reference letter.
  2. Choose MC to insert a material condition symbol for the primary datum reference.
  3. In the Material Condition dialog box, double-click a material condition symbol to insert it.
  4. Add secondary and tertiary datums and modifying symbols in the same way.
    • Now add a projected tolerance zone (optional).
  5. In the Height box, enter a height. Select Projected Tolerance Zone to insert the symbol.
  6. Choose OK.
  7. In the drawing, specify a location for the feature control frame.
  8. Choose OK to close each dialog box.

Command line TOLERANCE

1 comment so far ↓

#1 Kai on 12.06.09 at 9:48 am

U all can find and easy notes for autocad just visit

Leave a Comment