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AS568-018 O-Ring Size
000 series · 1/16" cross section · Pneumatics, instrumentation, small static seals
Inside diameter × cross section
18.77 × 1.78 mm
0.739″ × 0.07″ ·
outside diameter 22.33 mm (0.879″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 0.739″ | 18.77 mm |
| Cross section (CS) | 0.07″ | 1.78 mm |
| Outside diameter (OD) | 0.879″ | 22.33 mm |
Outside diameter is not measured, it is derived: OD = ID + 2 × CS.
If your measured OD disagrees with this, trust the ID and cross section — measuring
across the outside of a flexible ring is the least reliable of the three.
If you measured a used one
A ring pulled out of service will measure smaller than 18.77 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -018 is very likely still the correct part. Ordering the size your worn ring measures is how the same failure repeats. More on this →
Nearby sizes in the 000 series
These share the same 1/16" cross section, so if the thickness is right but the diameter is off, your ring is probably one of these.
| Dash | ID (mm) | ID (in) | OD (mm) |
|---|---|---|---|
| -019 | 20.35 | 0.801″ | 23.9 |
| -017 | 17.17 | 0.676″ | 20.73 |
| -016 | 15.6 | 0.614″ | 19.15 |
| -020 | 21.95 | 0.864″ | 25.5 |