O-Rings
Among the myriad of different O-Ring dimension standards available, the AS568 is the United States’ most popular. It was previously designated as ARP 568 and is now maintained by the Society of Automotive Engineers. AS568 lists 369 different sizes of O-Rings with corresponding tolerances and dimensions. This standard features O-Rings in five different cross-sections, with inside diameters that range from 1/32” to 26”. Tube fitting boss seals are also included in AS568 as “-900” series O-Ring sizes, intended for use in MS33649 (superseded now by SAE-AS5202) straight thread tube fittings.
In addition, PSP offers a wide variety of metric and non-standard O-Rings. As a subset of the available metric sizes, PSP stocks several Japanese Industrial Standard (JIS B2401) sizes. If you require a special size or specific chemical resistance, PSP can create custom O-Rings, specially made to your specific requirements.
O-Rings For Straight Thread Tube Fitting Bosses
| Tube Size | Dimensions in Inches | Dimensions in Millimeters | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| AS568A | Dash # | O.D | Vol. (in³) | I.D. | ± | C/S | ± | I.D. | ± | C/S | ± |
| 901 | 3/32 | .0019 | .185 | .005 | .056 | .003 | 4.70 | 0.13 | 1.42 | 0.08 | |
| 902 | 2 | 1/8 | .0031 | .239 | .005 | .064 | .003 | 6.07 | 0.13 | 1.63 | 0.08 |
| 903 | 3 | 3/16 | .0037 | .301 | .005 | .064 | .003 | 7.65 | 0.13 | 1.63 | 0.08 |
| 904 | 4 | 1/4 | .0054 | .351 | .005 | .072 | .003 | 8.90 | 0.13 | 1.83 | 0.08 |
| 905 | 5 | 5/16 | .0062 | .414 | .005 | .072 | .003 | 10.51 | 0.13 | 1.83 | 0.08 |
| 906 | 6 | 3/8 | .0082 | .468 | .005 | .078 | .003 | 11.90 | 0.13 | 1.98 | 0.08 |
| 907 | 7/16 | .0102 | .530 | .007 | .082 | .003 | 13.46 | 0.18 | 2.08 | 0.08 | |
| 908 | 8 | 1/2 | .0137 | .644 | .009 | .087 | .003 | 16.36 | 0.23 | 2.20 | 0.08 |
| 909 | 9/16 | .0186 | .706 | .009 | .097 | .003 | 17.93 | 0.23 | 2.46 | 0.08 | |
| 910 | 10 | 5/8 | .0198 | .755 | .009 | .097 | .003 | 19.18 | 0.23 | 2.46 | 0.08 |
| 911 | 11/16 | .0326 | .863 | .009 | .116 | .004 | 21.92 | 0.23 | 2.95 | 0.10 | |
| 912 | 12 | 3/4 | .0345 | .924 | .009 | .116 | .004 | 23.47 | 0.23 | 2.95 | 0.10 |
| 913 | 13/16 | .0366 | .986 | .010 | .116 | .004 | 25.04 | 0.25 | 2.95 | 0.10 | |
| 914 | 7/8 | .0386 | 1.047 | .010 | .116 | .004 | 26.62 | 0.25 | 2.95 | 0.10 | |
| 916 | 16 | 1 | .0427 | 1.171 | .010 | .116 | .004 | 29.74 | 0.25 | 2.95 | 0.10 |
| 918 | 1-1/8 | .0489 | 1.355 | .012 | .116 | .004 | 34.42 | 0.30 | 2.95 | 0.10 | |
| 920 | 20 | 1-1/4 | .0547 | 1.475 | .014 | .118 | .004 | 37.46 | 0.36 | 3.00 | 0.10 |
| 924 | 24 | 1-1/2 | .0631 | 1.720 | .014 | .118 | .004 | 43.70 | 0.36 | 3.00 | 0.10 |
| 928 | 28 | 1-3/4 | .0759 | 2.090 | .018 | .118 | .004 | 53.10 | 0.46 | 3.00 | 0.10 |
| 932 | 32 | 2 | .0843 | 2.337 | .018 | .118 | .004 | 59.36 | 0.46 | 3.00 | 0.10 |
The 900 series boss seals are designed to seal straight thread tube fittings when they are fastened into a boss. In this type of fitting the O-Ring is not located in a conventional rectangular groove. Rather, the seal is obtained when the gland components exert a diagonal squeeze through the O-Ring cross section.
