Engineering workspace · free
O-ring Engineer Pro: check the gland before you order
Rod, piston, face and dynamic seals in one workspace: squeeze, stretch, gland fill, extrusion clearance and material screening. Start from a size, a part number or a groove, then buy the exact size in stock or send the case for review.
- 4sealing modes
- 394AS568 sizes built in
- 77k+listed sizes to buy
- 1 · MediaScreen the chemical
- 2 · MaterialPick the family
- 3 · GlandCheck it here
- 4 · Buy or quoteExact size in stock
Reference geometry checks against public design ranges, not an engineering approval. Material results are family-level screening, not approval of a compound. Send the case for review when the seal is critical.
Backup-ring gland-width references
Use the chart for the listed service type and dash range. G0, G1 and G2 are widths for zero, one and two backup rings. Dimensions below are in inches.
Review pressure, effective extrusion clearance, hardness and pressure direction together when deciding whether backup rings are needed. Recheck squeeze, gland fill, material and assembly geometry after adding them.
Reciprocating gland widths - AS4716 design context
| Dash range | O-ring CS | G0: no backup | G1: one backup | G2: two backups |
|---|---|---|---|---|
| 001 | 0.037–0.043 | 0.070–0.075 | Not listed | Not listed |
| 002 | 0.047–0.053 | 0.077–0.082 | Not listed | Not listed |
| 003 | 0.057–0.063 | 0.088–0.093 | Not listed | Not listed |
| 004-009 | 0.067–0.073 | 0.098–0.103 | 0.154–0.164 | 0.210–0.220 |
| 010-028 | 0.067–0.073 | 0.094–0.099 | 0.150–0.160 | 0.207–0.217 |
| 110-149 | 0.100–0.106 | 0.141–0.151 | 0.183–0.193 | 0.245–0.255 |
| 210-247 | 0.135–0.143 | 0.188–0.198 | 0.235–0.245 | 0.304–0.314 |
| 325-349 | 0.205–0.215 | 0.281–0.291 | 0.334–0.344 | 0.424–0.434 |
| 424-460 | 0.269–0.281 | 0.375–0.385 | 0.475–0.485 | 0.579–0.589 |
Keep this source-chart route separate from other static or reciprocating gland designs. A blank backup-width cell has no listed source value; do not interpolate it or add a generic backup-ring thickness.
Static external gland widths - AS5857 design context
| Dash range | O-ring CS | G0: no backup | G1: one backup | G2: two backups |
|---|---|---|---|---|
| 001 | 0.037–0.043 | 0.090–0.095 | Not listed | Not listed |
| 002 | 0.047–0.053 | 0.095–0.100 | Not listed | Not listed |
| 003 | 0.057–0.063 | 0.105–0.110 | Not listed | Not listed |
| 004-007 | 0.067–0.073 | 0.115–0.120 | 0.174–0.184 | 0.230–0.240 |
| 008-028 | 0.067–0.073 | 0.105–0.110 | 0.164–0.174 | 0.220–0.230 |
| 104-109 | 0.100–0.106 | 0.150–0.160 | 0.210–0.220 | 0.275–0.285 |
| 110-149 | 0.100–0.106 | 0.140–0.150 | 0.200–0.210 | 0.265–0.275 |
| 210-247 | 0.135–0.143 | 0.185–0.195 | 0.250–0.260 | 0.320–0.330 |
| 325-349 | 0.205–0.215 | 0.270–0.280 | 0.360–0.370 | 0.455–0.465 |
| 425-460 | 0.269–0.281 | 0.345–0.355 | 0.475–0.485 | 0.610–0.620 |
Keep this source-chart route separate from other static or reciprocating gland designs. A blank backup-width cell has no listed source value; do not interpolate it or add a generic backup-ring thickness.
Design review
Design review checklist
Use these rules of thumb with the gland check above, then run the checklist before you release a design for production.
Gland design rules of thumb
For static and reciprocating (non-rotating) O-rings in oil, hydraulic fluid or other normal lubricants, with controlled machining tolerances.
- Gland fill
- Keep the O-ring cross-section at or below about 90% of the groove's cross-section area, leaving room for heat expansion and fluid swell. Above 100% the ring has nowhere to go: redesign the groove rather than force the fit.
- Installed stretch
- Keep stretch to about 3% when the ring is stretched into its groove. If the nearest standard size needs more, a different or custom size is usually better than overstretching.
- Extrusion gap
- The clearance a seal can bridge depends on system pressure and O-ring hardness. If the gap is too large for the pressure, tighten the tolerance, choose a harder compound or add a backup ring.
- Face seals
- Seat the ring against the groove wall on the side away from the pressure: the outer wall when pressure is inside, the inner wall when it is outside. Pressure then cannot push the ring across the groove.
- When these rules don't apply
- High pressure, wide tolerances, very low friction targets or other fluids need the seal and groove design confirmed by test or engineering analysis.
Check before production
Review each point for the actual installation and service conditions.
- Gland geometryGroove depth, width and fill for this installation
- Compression setSqueeze the ring won't recover after long periods under load; depends on compound, temperature and time
- Extrusion and nibblingAt high pressure; consider a backup ring
- Chemical compatibilityWith every fluid, cleaner and lubricant the seal touches
- Service temperatureNormal and peak
- AbrasionIn moving (dynamic) applications
- Surface finishOf the sealing faces and the groove
- Lubrication and frictionAt assembly and in service
- SwellingFrom chemical exposure; recheck gland fill
- HardnessAgainst pressure, extrusion gap and service conditions
Then test the chosen compound and seal design in the real installation before production use.