---
type: "o-ring"
dash_number: "431"
designation: "AS568-431"
cs_series: "425-475"
cs_series_name: "AS568 1/4 in series"
id_in: 5.225
id_mm: 132.72
cs_in: 0.275
cs_mm: 6.99
od_in: 5.775
od_mm: 146.7
id_tol_in: 0.037
cs_tol_in: 0.0059
standard: "SAE AS568; MIL-G-5514G (public domain, inactive for new design)"
verified: "August 1, 2026"
url: https://shopmath.org/o-rings/as568-431
---

# AS568-431 O-Ring Size — ID, Cross-Section and OD

An AS568-431 o-ring has an inside diameter of 5.2250 in (132.720 mm) and a 0.2750 in (6.990 mm) cross-section, for an outside diameter of 5.7750 in (146.700 mm). It belongs to the AS568 1/4 in series band.

- **Dash number**: 431
- **Cross-section series**: AS568 1/4 in series
- **Inside diameter**: 5.2250 in (132.720 mm)
- **Cross-section**: 0.2750 in (6.990 mm)
- **Outside diameter**: 5.7750 in (146.700 mm)
- **Standard**: SAE AS568; MIL-G-5514G (public domain, inactive for new design)

## AS568-431 Dimensions and Tolerances

| Dimension | Inch | Millimetre |
| --- | --- | --- |
| Inside diameter (ID) | 5.2250 | 132.720 |
| Cross-section (CS) | 0.2750 | 6.990 |
| Outside diameter (OD) | 5.7750 | 146.700 |
| ID tolerance | ±0.0370 | ±0.940 |
| CS tolerance | ±0.0059 | ±0.150 |

_Outside diameter is computed as ID + 2 × CS; AS568 tabulates ID and CS._

## Gland Design for AS568-431

Static gland dimensions for the 0.275 in cross-section. Depth is the groove depth that produces the stated squeeze on a nominal ring.

| Application | Squeeze | Squeeze (in) | Gland depth (in) | Gland depth (mm) |
| --- | --- | --- | --- | --- |
| Static face seal | 21–29% | 0.0578 – 0.0798 | 0.1953 – 0.2173 | 4.961 – 5.519 |

_Gland depth is computed as CS − (CS × squeeze %), then checked against the published design charts. Groove width, corner radius and back-up ring allowances are outside this dataset._

## O-Ring Sizes Closest to AS568-431

Nearest AS568 sizes by inside diameter — the substitutes to check when this one is out of stock.

| Size | ID (in) | ID (mm) | CS (in) | OD (in) |
| --- | --- | --- | --- | --- |
| [AS568-355](https://shopmath.org/o-rings/as568-355.md) | 5.2250 | 132.720 | 0.2100 | 5.6450 |
| [AS568-252](https://shopmath.org/o-rings/as568-252.md) | 5.2340 | 132.940 | 0.1390 | 5.5120 |
| [AS568-160](https://shopmath.org/o-rings/as568-160.md) | 5.2370 | 133.020 | 0.1030 | 5.4430 |
| [AS568-050](https://shopmath.org/o-rings/as568-050.md) | 5.2390 | 133.070 | 0.0700 | 5.3790 |
| [AS568-251](https://shopmath.org/o-rings/as568-251.md) | 5.1090 | 129.770 | 0.1390 | 5.3870 |
| [AS568-356](https://shopmath.org/o-rings/as568-356.md) | 5.3500 | 135.890 | 0.2100 | 5.7700 |

## Sources and Method for AS568-431

### AS568 dimensions

- **Source**: bd_warehouse o-ring_parameters.csv (Apache-2.0) and bckasper3/KasperCalc oring-sizes.js (MIT), agreeing on all 349 sizes; OD computed as ID + 2 x CS
- **Method**: computed+compiled
- **Verified against**: two independent open datasets agreeing on all 349 sizes; fabricated-dataset negative control passed; 21 checks total

### Gland design

- **Source**: MIL-G-5514G (public domain) gland design criteria; squeeze-percentage bands cross-read from Parker O-Ring Handbook ORD-5700 Design Charts 4-2/4-3 (verification only); depth = CS - CS x squeeze%
- **Method**: computed
- **Verified against**: computed depth band brackets the published design-chart band for every series

### Assumptions

- Dimensions are for a nominal, unstretched ring at room temperature. Installed stretch reduces cross-section.
- Gland figures are static-application only and assume a nominal ring; they carry no compound, temperature or pressure assumption.
- Dataset scope: A fabricated-dataset negative control is asserted against on every run. EXCLUDED: groove width, corner radius, diametral clearance, back-up ring widths, surface finish, all dynamic glands, the 900-series, and ISO 3601 metric sizes.

**Data last verified**: August 1, 2026

## Common Questions About the AS568-431 O-Ring

### What size is an AS568-431 o-ring?

AS568-431 has an inside diameter of 5.2250 in (132.720 mm) and a cross-section of 0.2750 in (6.990 mm), giving an outside diameter of 5.7750 in (146.700 mm).

### What is the o-ring size tolerance on AS568-431?

The AS568 tolerance on AS568-431 is ±0.0370 in (±0.940 mm) on the inside diameter and ±0.0059 in (±0.150 mm) on the cross-section.

### What groove depth does an AS568-431 o-ring need?

For a static face seal, an 0.275 in cross-section needs a gland depth of 0.1953 to 0.2173 in (4.961 to 5.519 mm), which puts the ring at 21–29% squeeze.

### What o-ring is closest in size to AS568-431?

The nearest AS568 sizes by inside diameter are AS568-355 (5.2250 in ID), AS568-252 (5.2340 in ID), AS568-160 (5.2370 in ID).

## Related pages

- Previous dash number: [AS568-430](https://shopmath.org/o-rings/as568-430.md) — 5.1000 in ID
- Next dash number: [AS568-432](https://shopmath.org/o-rings/as568-432.md) — 5.3500 in ID
- All o-ring sizes: [AS568 o-ring reference](https://shopmath.org/o-rings.md)
- Full size chart: [AS568 o-ring size chart](https://shopmath.org/charts/o-ring-sizes.md)

---

*Source: [ShopMath](https://shopmath.org/o-rings/as568-431) — data verified August 1, 2026. Reference data; verify against the governing standard before manufacture.*