The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-237-2137, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. Government technical data includes 22 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-237-2137 |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Status | ACTIVE |
| Surface Finish | 63.0 MICROINCHES GRIP |
| Surface Finish | 63.0 MICROINCHES BEARING SURFACE OF HEAD |
| Head Height | 0.157 INCHES MINIMUM AND 0.172 INCHES MAXIMUM IN |
| Fastener Length | 2.728 INCHES MINIMUM AND 2.748 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TYPE 2,CLASS 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.311 INCHES MINIMUM AND 0.378 INCHES MAXIMUM IN |
| Hardness Rating | 36.0 ROCKWELL C MINIMUM AND 41.0 ROCKWELL C MAXIMUM OVERALL |
| Shank Unthreaded Hole Diameter | 0.076 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN |
| Nominal Thread Diameter | 0.312 INCHES IN |
| Head Style | DISHED HEXAGON |
| Thread Direction | RIGHT-HAND |
| Grip Length | 2.250 INCHES MINIMUM AND 2.266 INCHES MAXIMUM IN |
| Width Between Flats | 0.492 INCHES MINIMUM AND 0.502 INCHES MAXIMUM IN |
| Grip Diameter | 0.3108 INCHES MINIMUM AND 0.3117 INCHES MAXIMUM IN |
| Locking Feature | DETENT RING GRIP |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 95000 POUNDS PER SQUARE INCH LBS |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 24 |
| Material | STEEL COMP E4340 OR STEEL COMP 4140 OR STEEL COMP 8740 OR STEEL COMP 4130 OR STEEL COMP 6150 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 2.613 INCHES MINIMUM AND 2.643 INCHES MAXIMUM FIRST HOLE IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| MS27576-5-36 | 5/9 Secondary reference U.S. Government activity |
| MS27576-5-36 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5306-01-237-2137 is a Bolt,close Tolerance, classified under FSC 5306, Bolts. Status: active.
Key specifications for 5306-01-237-2137: Surface Finish: 63.0 MICROINCHES GRIP; Surface Finish: 63.0 MICROINCHES BEARING SURFACE OF HEAD; Head Height: 0.157 INCHES MINIMUM AND 0.172 INCHES MAXIMUM IN; Fastener Length: 2.728 INCHES MINIMUM AND 2.748 INCHES MAXIMUM IN. 22 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.