nuts › plain hexagon nuts
AN818-6J
Aeronautical Standard Tube Coupling Nut
Description
Coupling Nut
Specifications
| Connection Type | Flared Tube |
|---|---|
| Diameter A | 0.440 in |
| Diameter C | 0.687 in |
| Dimension A Tolerance | +0.003 in |
| Dimension C Tolerance | +0.000 in |
| Dimension J | 0.500 in |
| Dimension M | 0.724 in |
| Dimension M Tolerance | +0.010 in |
| Dimension O | 0.688 in |
| Dimension O Tolerance | -0.004 in |
| Industry Standards/Certification | AN818 |
| Material | CRES |
| NIIN | 00-203-2661 |
| NSN | 4730-00-203-2661 |
| Nut Height | 0.719 |
| Nut Style | Tube coupling |
| Size No. Alum | 6D |
| Size No. SS | 6J |
| Size No. Steel | 6 |
| Surface Treatment | Passivate |
| Thread Class | 3b |
| Thread Direction | Right-hand |
| Thread Qty Per Inch (tpi) | 18 |
| Thread Series | Unf (fine thread) |
| Thread Size | 0.562, 9/16-18 |
| Thread T (MIL-S-8879) | 0.5625-18 |
| Tube O.D. | 3/8 |
| Tube Outside Diameter | 0.375 in |
| Weight | 0.04 lb |
| Width Across Flats | Between 0.684 inches and 0.691 inches |
Cross-reference
Similar parts
Parts with matching key dimensions — often from a different standards family. Candidates for comparison only; verify the full specification before substituting.
Looking for a specific part? Use the cross-reference lookup.
Catalog data updated 2026-07-05. Report a data error