The document discusses dimensional tolerances in engineering drawings. It defines tolerances for shafts and holes using international tolerance (IT) grades. Lowercase letters indicate tolerances for shafts, while uppercase letters are used for holes. The document provides an example of calculating the tolerance for a 40mm shaft with an IT8 grade tolerance, showing the tolerance is 39μ, with a g8 deviation meaning the minimum size is 39.952mm. Dimensional tolerances are important for specifying permissible variation in manufactured component sizes.

1. 1. PART AND ASSEMBLY 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: HELICAL
12. GEARS 3: BEVEL
13. BELTS AND CHAINS
14. WELDED JOINTS AND RIVETS
3. DIMENSIONAL TOLERANCES

2. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
These are called shafts
These are called holes

3. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
These are the
names we should
be familiar with.
shaft
hole

4. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
We can indicate dimensional
tolerances in this way

5. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
TOLERANCE GRADES
But the ISO groups recommend us
to use tolerance grades…

6. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
Where do they come from?
TOLERANCE GRADES
(IT stands for International Tolerance)

7. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
Tolerance on a shaft or a hole can also be calculated by using the formulas provided by ISO.
iKT ×=
T is the tolerance (in mm)
DDi 001.045.0 3
+= (unit tolerance, in mm)
21DDD = (D1 and D2 are the nominal sizes marking the beginning and
the end of a range of sizes, in mm)
( )( )6
6.110 ITITnK −
=
Tolerance Designation (ISO R286)

8. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
Example:
Calculate the tolerance on the shaft (D=25 mm and IT grade of 7) using the
formulas given in ISO standards.
i = 1.3073 mm
( )( )
166.110 67
== −
K
mm0.021m91.20 ==×= µiKTs
Tolerance Designation (ISO R286)

9. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
With ITs we will know the tolerance,
but not the position (in the hole or in
the shaft) It will be defined by
deviations …
We use CAPITAL letters for holes…

10. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio

11. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
We use small letters for shafts…

12. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio

13. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
Remember H and h positions!

14. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
Tolerances in drawing:
nominal size + zone + grade

15. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
What is meant by the tolerance 40g8?

16. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
1. Draw the zero line and the shaft tolerance
What is meant by the tolerance 40g8?
You must know that “g” is below the zero line

17. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8
ø40
What is meant by the tolerance 40g8?
Zero line

18. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8 39µ
ø40
What is meant by the tolerance 40g8?
Zero line

19. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8 39µ
ø40
3. Evaluate deviations (fundamental deviation table – slide 12)
g8 es=
ø40
What is meant by the tolerance 40g8?
Zero line

20. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8 39µ
ø40
3. Evaluate deviations (fundamental deviation table – slide 12)
g8 es=-9µ | ei
ø40
What is meant by the tolerance 40g8?
Zero line

21. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8 39µ
ø40
3. Evaluate deviations (fundamental deviation table – slide 12)
g8 es=-9µ | ei=es-t=-9-39=-48µ
ø40
What is meant by the tolerance 40g8?
Zero line

22. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
2. Calculate its TOLERANCE (IT grade-basic size table – slide 5)
1. Draw the zero line and the shaft tolerance
IT8 39µ
ø40
3. Evaluate deviations (fundamental deviation table – slide 12)
g8 es=-9µ | ei=es-t=-9-39=-48µ
ø40
4. Solution:
Maximum limit of size: 40-0,009=39,991 mm
Minimum limit of size: 40-0,048=39,952 mm
What is meant by the tolerance 40g8?
Zero line

23. DIMENSIONAL TOLERANCES DEFINITIONS | ANNOTATION| ISO
Industrial Drawing
CC 2015 Ramón Rubio
What is meant by the tolerance 40g8?
We can also indicate the minimum and maximum values

24. 1. PART AND ASSEMBLY 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: HELICAL
12. GEARS 3: BEVEL
13. BELTS AND CHAINS
14. WELDED JOINTS AND RIVETS
3. DIMENSIONAL TOLERANCES