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O-Rings & Related  Products

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 Tube fitting boss seals are also included in AS568 as “-900” series O-Ring sizes, intended for use in MS33649 (superseded now by SAE-AS5202) straight thread tube fittings.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, J Royal offers a wide variety of metric and non-standard O-Rings. As a subset of the available metric sizes, J Royal stocks several Japanese Industrial Standard (JIS B2401) sizes. If you require a special size or specific chemical resistance, J Royal 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.