The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-168-5631, 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 19 specifications, cited from the U.S. Government catalog. The record lists 6 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-168-5631 |
| Primary Part Number | ST3M731-4-19 |
| 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 | 1.598 INCHES MINIMUM AND 1.628 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | MIL-C-83488,TYPE 2,CL 3 MIL SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.400 INCHES MINIMUM AND 0.450 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 4967 COMP 6AL-4V ASSN STD SINGLE MATERIAL RESPONSE OVERALL V |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.178 INCHES MINIMUM AND 1.198 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 AND CHROMATE OVERALL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | TITANIUM ALLOY OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| 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 |
|---|---|
| SC2663-4-19 | Howmet Global Fastening Systems Inc (USA) |
| MB251-4-19 | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| 111364-4-19 | Sps Technologies Ltd, Tj Brooks Division (GBR) |
| ST3M731-4-19 PRIMARY | The Boeing Company Div Defense (USA) |
| PBF1264-4-19 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| MB251-4-19 | Hi-Shear Corporation (USA) |
| Reference | Meaning |
|---|---|
| ST3M731-4-19 | 5/9 Secondary reference U.S. Government activity |
| VS3207-4-19 | 5/9 Secondary reference Howmet Global Fastening Systems Inc |
| 801651-4-19 | 5/9 Secondary reference Sps Technologies Inc |
| VS3207-4-19 | 5/9 Secondary reference U.S. Government activity |
| 111364-4-19 | 5/2 Secondary reference U.S. Government activity |
| 10116066 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
NSN 5306-01-168-5631 is a Bolt,close Tolerance, manufactured by The Boeing Company Div Defense, classified under FSC 5306, Bolts. Status: active.
NSN 5306-01-168-5631 has 6 manufacturer part numbers on file: SC2663-4-19 (Howmet Global Fastening Systems Inc), MB251-4-19 (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), 111364-4-19 (Sps Technologies Ltd, Tj Brooks Division), ST3M731-4-19 (The Boeing Company Div Defense), PBF1264-4-19 (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners) and 1 more.
Key specifications for ST3M731-4-19: 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. 19 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.