According to the requirements of machining method and assembly accuracy, the appropriate it tolerance grade value shall be selected for dimensioning. The dimension without tolerance indication in the drawing shall be specified according to the requirements of GB / t1804-2000 “linear and angular dimensional tolerances without tolerance indication”.
Limit deviation value of linear dimension
|
Tolerance class |
0~3 |
>3~6 |
>6~30 |
>30~120 |
>120~400 |
>400~1000 |
>1000~2000 |
>2000 |
|
Precision f |
±0.05 |
±0.05 |
±0.1 |
±0.15 |
±0.2 |
±0.3 |
±0.5 |
— |
|
Medium M |
±0.1 |
±0.1 |
±0.2 |
±0.3 |
±0.5 |
±0.8 |
±1.2 |
±2.0 |
|
Rough C |
±0.2 |
±0.3 |
±0.5 |
±0.8 |
±1.2 |
±2.0 |
±3.0 |
±4.0 |
|
Thickest V |
— |
±0.5 |
±1.0 |
±1.5 |
±2.5 |
±4.0 |
±6.0 |
±8.0 |
Limit deviation value of fillet radius and chamfer height
| Tolerance class |
0~3 |
3~6 |
>6~30 |
>30 |
|
Precision f |
±0.2
|
±0.5
|
±1.0
|
±2.0
|
|
Medium M |
||||
|
Rough C |
±0.4
|
±1.0
|
±2.0
|
±4.0
|
|
Thickest V |
Limit deviation value of angle dimension
| Tolerance class |
0~10 |
>10~50 |
>50~120 |
120~400 |
>400 |
|
Precision f |
±1° |
±30′ |
±20′ |
±10′ |
±5′ |
|
Medium M |
|
|
|
|
|
|
Rough C |
±1°30′ |
±1° |
±30′ |
±15′ |
±10′ |
|
Thickest V |
±3° |
±2° |
±1° |
±30′ |
±20′ |
General drawing representation without tolerance indication
Mark the standard number and tolerance grade code near the title block of the drawing or in the technical requirements and technical documents (such as enterprise standards). For example, when selecting the medium level, the label is as follows:
GB/T 1804-m
Structures not marked with geometric tolerance in drawings shall be marked according to the grade in GB / t1184-1996 “geometrical and positional tolerances without individual tolerance values”. [1]
|
Tolerance class |
0~10 |
>10~30 |
>30~100 |
>100~300 |
>300~1000 |
>1000 |
|
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 |
Straightness and flatness without tolerance
|
Tolerance class |
0~100 |
>100~300 |
>300~1000 |
>1000 |
|
H |
0.2 |
0.3 |
0.4 |
0.5 |
|
K |
0.4 |
0.6 |
0.8 |
1 |
|
L |
0.6 |
1 |
1.5 |
2 |
Symmetry without tolerance
|
Tolerance class |
0~100 |
>100~300 |
>300~1000 |
>1000 |
|
H |
0.5 |
|||
|
K |
0.6 |
0.8 |
1 |
|
|
L |
0.6 |
1 |
1.5 |
2 |
Circular runout without tolerance
|
Tolerance class |
Circle runout tolerance |
|
H |
0.1 |
|
K |
0.2 |
|
L |
0.5 |
Post time: Oct-12-2020