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ISO 2768-1:1989

View:     Time: 2017-6-6 15:07:38

General tolerances for linear and angular dimensions without individual tolerance indications ISO 2768-1:1989

All features on component parts always have a size and a geometrical shape. For the deviation of size and for the deviations of the geometrical characteristics (form,orientation and location) the function of the part requires limitations which, when exceeded, impair this function.The tolerance on the drawing should be complete to ensure that the elements of size and geometry of all features are controlled, i.e. nothing shall be implied or left to judgement in the workshop or in the inspection department.The use of general tolerances for size and geometry simplifies the task of ensuring that this prerequisite is met.

General tolerances for linear dimensions are given in Table 1 and Table 2.
The permissible deviations of angular dimensions are given in Table 3.

Table 1  Permissible deviations for linear dimensions except for broken edges 
(external radii and chamfer heights, see Table 2)
Tolerance calss Permissible deviations for basic size range
DesignationDescription 0.5 
up to
  3
 over 
  3
up to
  6 
 over
  6
up to
  30 
over
 30 
up to
 120
over
 120
up to
 400
over
400
up to
1000
over
1000
up to
2000
over
2000
up to
4000
ffine ±0.05±0.05±0.1±0.15±0.2±0.3±0.5--
mmedium±0.1±0.1±0.2±0.3±0.5±0.8±1.2±2
ccoarse±0.2±0.3±0.5±0.8±1.2±2±3±4
vvery coarse--±0.5±1±1.5±2.5±4±6±8
For nominal sizes below 0,5 mm, the deviations shall be indicated adjacent to the relevant nominal size(s).


Table 2  Permissible deviations for broken edges (external radii and chamfer heights)
Tolerance calss Permissible deviations for basic size range
DesignationDescription 0.5 
up to
  3
 over 
  3
up to
  6 
over 6
ffine ±0.2±0.5±1
mmedium
ccoarse±0.4±1±2
vvery coarse
aFor nominal sizes below 0,5 mm, the deviations shall be indicated adjacent to the relevant nominal size(s).

Table3-permissible deviations of angular dimensions
Tolerance classpermissible deviations for ranges of lengths,in millimetres
of shorter side of the angle concerned
DesignationsDescriptions   up to 10over 10up to 50   over 50 up to 120over 120 up to 400       over 4
ffine±1° ±0°30´   ±0°20´±0°10´     ±0°5´ 
mmedium
ccoarse±1°30´±1°  ±0°30´±0°15´     ±0°10´ 
vvery coares±3°±2°±1° ±0°30´     ±0°20´