Standard GB/T1804-m & ISO 2768-1/2

GB/T1804

GB/T1804 is a Chinese standard. The “-m” indicates the tolerance class.

This standard is equivalent to ISO 2768.

Detail Information of GB/T 1804-2000
Description : General tolerances Tolerances for linear and angular dimensions without individual tolerance indications
Sector / Industry: China National Standard
Classification of Chinese Standard: J04
Classification of International Standard: 17.040.10
Date of Issue: 2000-07-24
Date of Implementation: 2000-12-01
Older Standard (superseded by this standard): GB/T 1804-1992; GB/T 11335-1989
Quoted Standard: GB/T 1800.1-1997; GB/T 1184-1996; GB/T 4249-1996; GB/T 6403.4-1986
Adopted Standard: ISO 2768-1-1989, MOD

Drafting Organization: Mechanical Engineering Research Institute
Administrative Organization: National product size and geometry specifications Standardization Technical Committee
Proposing organization: National Machinery Industry Bureau
Issuing agency(ies): State Quality and Technical Supervision

Summary:

This standard specifies the satellite broadcast system integration down converter technical requirements and methods of measurement.

For the same measurement uncertainty can ensure that any equivalent measurement methods may also be used. Dispute should be based on this standard shall prevail.

This standard applies to radio and television satellite broadcast system integrated down converter development, production, use, and operation and maintenance.

ISO 2768

ISO Tolerances

According to DIN ISO 2768-1

General tolerances for linear measures and level squares with four tolerance classes are useful for simplifying drawings.

By choosing the tolerance class precision levels common in workshops should be taken into account.

If smaller tolerances are needed or bigger ones are more economical,
then these tolerances are indicated next to the nominal size.

Tabular 1 Limits for linear measures

Tolerance-class

Limits in mm for nominal sizes in mm

0.5 to 3

above
3 to 6

above    6 to 30

above   30 to 120

above 120 to 400

above 400
to 1000

above 1000
to 2000

above 2000
to 4000

f (fine)

± 0.05

± 0.05

± 0.1

± 0.15

± 0.2

± 0.3

± 0.5

m (medium)

± 0.1

± 0.1

± 0.2

± 0.3

± 0.5

± 0.8

± 1.2

± 2

c (coarse)

± 0.15

± 0.2

± 0.5

± 0.8

± 1.2

± 2

± 3

± 4

v (very coarce grob)

± 0.5

± 1

± 1.5

± 2.5

± 4

± 6

± 8

For nominal sizes below 0,5 mm the limit measures are to be indicated directly at the nominal measure.

Tabular 2 Limit measures for radius of curvature and chamfer height

Toleranceclass

Limits in mm for nominal sizes in mm

0.5

to 3

above 3

to 6

above 6

f (finne)

± 0.2

± 0,5

± 1

m (medium)
c (coarse)

± 0.4

± 1

± 2

v (very coarse)

Bei Nennmassen unter 0.5 mm sind die Grenzabmasse direkt am Nennmass anzugeben.

Tabelle 3 Grenzabmasse für Winkelmasse

Tolerance class

Limits in mm for nominal sizes in mm

to 10

above 10

to 50

above 50

to 120

above 50

to 400

above 400

f (fine)

± 1 °

± 30 ‘

± 20 ‘

± 10 ‘

± 5 ‘

m (medium)
c (coarse )

± 1 ° 30 ‘

± 1 °

± 30 ‘

± 15 ‘

± 10 ‘

v (very coarce)

± 3 °

± 2 °

± 1 °

± 30 ‘

± 20 ‘

For nominal sizes below 0.5 mm the limit measures are to be indicated directly at the nominal measure. If general tolerances according to ISO 2768-1 are valid,
the following has to be inserted in the title box, i.e. for tolerance class medium

ISO 2768 – m or general tolerance ISO 2768 – m

For new designs only the general tolerance according to DIN ISO 2768-1 should be valid. The limit measurements of the tolerance classes m and f of DIN ISO 2768-1 are identic with those of DIN 7168-1.

ISO Tolerances

According to DIN ISO 2768-2

DIN ISO 2768-2 is for simplifying drawing and fixes general tolerances in three tolerance classes for form and position.
By choosing a special tolerance class exactly the precision level common in workshops should be taken into account.

If smaller tolerances are needed or bigger are more economical these tolerances should be mentioned directly according to ISO 1101.

General tolerances for form and position should be used while the tolerance principle according. to ISO 8015 is valid and while this is mentioned in the drawing.
This tolerance principles says that no opposite relation between measure, form and position tolerance exists (principle of superposition).

Toleranceclass

General tolerances for straightness and evenness in mm

Range of specified size in mm

to 10

above 10

to 30

above 30

to 100

above 100

to 300

above 300

to 1000

above 1000

to 3000

H

0.02

0.05

0.1

0.2

0.3

0.4

K

0.05

0.1

0.2

0.4

0.6

0.8

L

0.1

0.2

0.4

0.8

1.2

1.6

Toleranceclass

General tolerances for straightness and evenness in mm

Range of specified size in mm

to 100

above 100

to 300

above 300

to 1000

above 1000

to 3000

H

0.2

0.3

0.4

0.5

K

0.4

0.6

0.8

1

L

0.6

1

1.5

2

Toleranceclass

General tolerances for symmetry

Range of specified size in mm

to 100

above 100

to 300

above 300

to 1000

above 1000

to 3000

H

0.5

K

0.6

0.8

1

L

0.6

1

1.5

2

General tolerances for form and position are valid for form elements for which form and position tolerances are not indicated individually.
They are applicable for all characteristics of the form elements accept cylinders, profiles of any line or surfaces, inclines, coaxiality, position and total movement.

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