05. Geometric tolerances

Geometric tolerances lesson

1. 1. WORKING DRAWINGS
2. SURFACE CHARACTERISTICS
3. DIMENSIONAL TOLERANCES
4. FITS
5. GEOMETRIC TOLERANCES
6. DIMENSIONING
7. THREADED FASTENING
8. SHAFT AND PIPE JOINERS
9. BEARINGS
10. GEARS 1: DEFINITION
11. GEARS 2: BEVEL AND HELICAL
12. BELTS AND CHAINS
13. WELDED JOINTS AND RIVETS
14. INDUSTRIAL DESIGN METHODOLOGY
15. SIMULATION
5. GEOMETRIC TOLERANCES

2. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
Sometimes, dimensional tolerances are not enough
to ensure the function of a part in a mechanism.

3. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
So we add some information that complements
dimensions. It is known as GD&T (Geometric
Dimensioning & Tolerancing)

4. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
Let us see an example of WHY geometric
tolerances are so important.
We design a table and the height has a tolerance.
Assume all 4 legs are cut at the same time.

5. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
As the table height is dimensioned, the following table would
pass inspection.

6. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
But …look at the table! It’s not flat, but inclined.
Despite that, the table would pass.

7. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
You can solve that, by using GD&T.
• The table may be any height between 26 and 28 inches.
• The table top must be flat within 1/16. (±1/32)
26
.06

8. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
Feature Control Frame: It’s the main part of GD&T

9. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES

10. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
The arrow of the frame:
1. Pointing at the surface: Indicates the
reference surface
2. If it is an extension of the dimension line,
it will indicate the axis or symmetry plane
3. Pointing at the axis means that the tolerance for all the elements is related to that axis.

11. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
FORM > Straightness (Rectitud)
The straightness of the feature must be within .005 tolerance zone.

12. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
FORM > Straightness (Rectitud)

13. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
FORM > Flatness (Planicidad)
The tolerance zone is a zone held between two parallel planes a distance “t” apart

14. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
FORM > Flatness (Planicidad)
The tolerance zone is a zone held between two parallel planes a distance “t” apart

15. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
The real curve must be between two circumferences whose radii difference is the
tolerance.
FORM > Circularity (Redondez)

16. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
FORM > Cilindricity (Cilindricidad)
The real cylinder must be between two cylinders whose radii difference is the
tolerance.

17. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
ORIENTATION > Parallelism (Paralelismo)
The tolerance zone is a zone held between two parallel planes parallel to the datum
plane and a distance “t” apart from each other

18. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
ORIENTATION > Parallelism (Paralelismo)
The tolerance zone is a zone held between two parallel planes parallel to the datum
plane and a distance “t” apart from each other

19. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
The tolerance zone is a zone within a cylinder of diameter “t” perpendicular to the datum plane
ORIENTATION > Perpendicularity (Perpendicularidad)

20. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
ORIENTATION > Perpendicularity

21. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
ORIENTATION > Angularity (inclinación)
The tolerance zone is held between two parallel planes inclined at the specified angle to
the datum plane and separates “t” units from each other.

22. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
LOCATION > Positional (Posición)
The tolerance zone is a zone within a circle, cylinder or sphere of diameter “t” having its
centre at the theoretically exact location.

23. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
LOCATION > Positional (Posición)
The tolerance zone is a zone within a circle, cylinder or sphere of diameter “t” having its
centre at the theoretically exact location.

24. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
LOCATION > Coaxiality (Coaxialidad)
The tolerance zone is a zone within a cylinder of diameter “t” whose axis agrees with
the datum axial straight line.

25. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
LOCATION > Symmetry (Simetría)
The tolerance zone is held between two parallel planes a distance “t” apart from each
other and arranged symmetrically to the datum median plane.

26. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
RUN OUT > Circular run-out
The tolerance is a zone between two concentric circles whose centres agree with the
datum axial straightline on any measuring plane normal to the datum axial straightline.
They are a distance “t” apart from each other in the radial direction.

27. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
RUN OUT > Circular run-out
The tolerance is a zone between two concentric circles whose centres agree with the
datum axial straightline on any measuring plane normal to the datum axial straightline.
They are a distance “t” apart from each other in the radial direction.

28. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
RUN OUT > Circular run-out
The tolerance is a zone between two concentric circles whose centres agree with the
datum axial straightline on any measuring plane normal to the datum axial straightline.
They are a distance “t” apart from each other in the radial direction.

29. GEOMETRIC TOLERANCES
Industrial Drawing
CC 2015 Ramón Rubio
DEFINITIONS | EXAMPLES
RUN OUT > Total run-out
The tolerance is a zone between two coaxial cylinders having axes agreeing with the
datum axial straightline and a distance “t” apart from from each other in the radial
direction.

30. 1. WORKING DRAWINGS
2. SURFACE CHARACTERISTICS
3. DIMENSIONAL TOLERANCES
4. FITS
5. GEOMETRIC TOLERANCES
6. DIMENSIONING
7. THREADED FASTENING
8. SHAFT AND PIPE JOINERS
9. BEARINGS
10. GEARS 1: DEFINITION
11. GEARS 2: BEVEL AND HELICAL
12. BELTS AND CHAINS
13. WELDED JOINTS AND RIVETS
14. INDUSTRIAL DESIGN METHODOLOGY
15. SIMULATION
5. GEOMETRIC TOLERANCES