The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-188-6840, 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 9 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 12 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-188-6840 |
| Primary Part Number | ST3M571-6D24 |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | The Boeing Company Div Defense |
| Status | ACTIVE |
| Extended Washer Thickness | 0.081 INCHES MINIMUM AND 0.101 INCHES MAXIMUM IN |
| Head Height | 0.378 INCHES MINIMUM AND 0.398 INCHES MAXIMUM IN |
| Fastener Length | 2.099 INCHES MINIMUM AND 2.129 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Extended Washer Diameter | 0.639 INCHES MINIMUM AND 0.649 INCHES MAXIMUM IN |
| Thread Length | 0.589 INCHES MINIMUM AND 0.639 INCHES MAXIMUM IN |
| Shank Unthreaded Hole Diameter | 0.106 INCHES MINIMUM AND 0.111 INCHES MAXIMUM FIRST HOLE IN |
| Nominal Thread Diameter | 0.375 INCHES IN |
| Head Style | DOUBLE HEXAGON W/HOLE |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.490 INCHES MINIMUM AND 1.510 INCHES MAXIMUM IN |
| Width Between Flats | 0.429 INCHES MINIMUM AND 0.449 INCHES MAXIMUM IN |
| Grip Diameter | 0.3740 INCHES MINIMUM AND 0.3745 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 24 |
| Material | STEEL COMP XM-13 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 1.876 INCHES MINIMUM AND 1.916 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 |
| Part Number | Manufacturer |
|---|---|
| MB84-6D24 | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| ST3M571-6D24 | Howmet Global Fastening Systems Inc (USA) |
| MB84-6D24 | Hi-Shear Corporation (USA) |
| AIC752-6D24 | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| GS1030-6D24 | B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace (USA) |
| ST3M571-6D24 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| VAL23033-6D24 | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| ST3M571-6D24 PRIMARY | The Boeing Company Div Defense (USA) |
| S11-1059-6D24 | Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries (USA) |
| Reference | Meaning |
|---|---|
| S371-6D24 | C/1 Advisory reference — outside the item-of-supply concept Huck International, Inc |
| RA22018-6D24 | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| 74328-6D24 | 5/9 Secondary reference U.S. Government activity |
| ST3M571-6D24 | 5/9 Secondary reference Sps Technologies Inc |
| VS3060-6D24 | C/1 Advisory reference — outside the item-of-supply concept Howmet Global Fastening Systems Inc |
| BM3326-6D24 | C/1 Advisory reference — outside the item-of-supply concept Huck International, Inc |
| ST3M571-6D24 | C/1 Advisory reference — outside the item-of-supply concept Sps Technologies Llc Dba PB Fasteners Div PB Fasteners |
| S371-6D24 | 5/9 Secondary reference U.S. Government activity |
| BM3326-6D24 | 5/9 Secondary reference U.S. Government activity |
| 74328-6D24 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| VS3060-6D24 | 5/9 Secondary reference U.S. Government activity |
| RA22018-6D24 | C/1 Advisory reference — outside the item-of-supply concept Huck International, Inc |
NSN 5306-01-188-6840 is a Bolt,close Tolerance, manufactured by The Boeing Company Div Defense, classified under FSC 5306, Bolts. Status: active.
NSN 5306-01-188-6840 has 9 manufacturer part numbers on file: MB84-6D24 (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), ST3M571-6D24 (Howmet Global Fastening Systems Inc), MB84-6D24 (Hi-Shear Corporation), AIC752-6D24 (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), GS1030-6D24 (B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace) and 4 more.
Key specifications for ST3M571-6D24: Extended Washer Thickness: 0.081 INCHES MINIMUM AND 0.101 INCHES MAXIMUM IN; Head Height: 0.378 INCHES MINIMUM AND 0.398 INCHES MAXIMUM IN; Fastener Length: 2.099 INCHES MINIMUM AND 2.129 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL. 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.