The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-478-4738, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. The manufacturer of record is The Boeing Company Div Defense. Government technical data includes 22 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-478-4738 |
| Primary Part Number | ST3M731-4D27 |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | The Boeing Company Div Defense |
| Status | ACTIVE |
| Surface Finish | 63.0 MICROINCHES GRIP |
| Surface Finish | 63.0 MICROINCHES BEARING SURFACE OF HEAD |
| Surface Finish | 16.0 MICROINCHES THREADS |
| Head Height | 0.125 INCHES MINIMUM AND 0.140 INCHES MAXIMUM IN |
| Fastener Length | 2.098 INCHES MINIMUM AND 2.128 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | MIL-C-83488, TY 2, CL 3 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.425 INCHES NOMINAL IN |
| Shank Unthreaded Hole Diameter | 0.076 INCHES MINIMUM AND 0.086 INCHES MAXIMUM FIRST HOLE IN |
| Material Document and Classification | AMS4697, COMP 6AL-4V ASSN STD SINGLE MATERIAL RESPONSE OVERALL V |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Features Provided | FINISHED HEAD |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.678 INCHES MINIMUM AND 1.698 INCHES MAXIMUM IN |
| Width Between Flats | 0.430 INCHES MINIMUM AND 0.439 INCHES MAXIMUM IN |
| Grip Diameter | 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | ALUMINUM OVERALL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | TITANIUM ALLOY OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 1.932 INCHES NOMINAL 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 |
| Part Number | Manufacturer |
|---|---|
| ST3M731-4D27 PRIMARY | The Boeing Company Div Defense (USA) |
| Reference | Meaning |
|---|---|
| VS3207-4-27D | 3/2 Design control — primary reference U.S. Government activity |
NSN 5306-01-478-4738 is a Bolt,close Tolerance, manufactured by The Boeing Company Div Defense, classified under FSC 5306, Bolts. Status: active.
NSN 5306-01-478-4738 has 1 manufacturer part number on file: ST3M731-4D27 (The Boeing Company Div Defense).
Key specifications for ST3M731-4D27: Surface Finish: 63.0 MICROINCHES GRIP; Surface Finish: 63.0 MICROINCHES BEARING SURFACE OF HEAD; Surface Finish: 16.0 MICROINCHES THREADS; Head Height: 0.125 INCHES MINIMUM AND 0.140 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.