Metric O Rings
Dimensions of O-Rings have been published in various German and International Standards. In addition, there exist a variety of non-standard sizes.
Approved tolerances reflected in the table to the right refer to the compound Nitrile-Butadiene-Rubber in 70 Shore A resp. 73 IRHD.
Other compounds, however, vary considerably in their shrinkage rates and when produced from the same tooling are likely to come out with a wider tolerance. Special tooling can, of course, always be manufactured to produce exact sizes where application demands such accuracy.
d1
± tolerance
d2
± tolerance
to 3
3-6
6-10
10-18
18-30
30-50
50-80
80-100
100-120
120-150
150-180
180-250
250-300
300-350
350-400
450-500
550-600
650-800
.14
.15
.17
.20
.30
.40
.65
.85
1
1.2
1.4
1.8
2.1
2.5
2.8
3.4
4.3
6.5
to 1.8
1.8-2.6
2.6-3.5
3.5-5.3
5.3-7
7-8
8-10
10-15
.08
.09
.10
.13
.15
.17
.20
.25
  Compounds for O-Rings
Material
DIN Abbreviation
Hardness Shore A
Hardness IRHD
Color
Nitrile-Butadiene-Rubber
NB
70
73
Black
Nitrile-Butadiene-Rubber
NB
90
92
Black
Fluorocarbon-Rubber (Viton)
FP
75
78
Black
 Food grades and other compounds are available upon request
  British/Japanese Cross Reference Chart
Number
d2
G25-G145
G150-G300
P3-P10
P10A-P22
P22A-P50
P48A-P150
P150A-P400
S3-S22
S22.4-S150
V15-V175
V225-V430
V480-V1055
3.1
5.7
1.9
2.4
3.5
5.7
8.4
1.5
2
4
6
10