The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-027-5249, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. The manufacturer of record is Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc. Government technical data includes 17 specifications, cited from the U.S. Government catalog. The record lists 13 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 13 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-027-5249 |
| Primary Part Number | ST3M571-4-18 |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc |
| Status | ACTIVE |
| Extended Washer Thickness | 0.059 INCHES MINIMUM AND 0.079 INCHES MAXIMUM IN |
| Head Height | 0.290 INCHES MINIMUM AND 0.310 INCHES MAXIMUM IN |
| Fastener Length | 1.578 INCHES MINIMUM AND 1.608 INCHES MAXIMUM IN |
| Extended Washer Diameter | 0.428 INCHES MINIMUM AND 0.438 INCHES MAXIMUM IN |
| Thread Length | 0.443 INCHES MINIMUM AND 0.493 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5629 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | DOUBLE HEXAGON W/HOLE |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.115 INCHES MINIMUM AND 1.135 INCHES MAXIMUM IN |
| Width Between Flats | 0.304 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN |
| Grip Diameter | 0.2490 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP XM-13 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 |
|---|---|
| ST3M571-4-18 | Saturn Fasteners Inc (USA) |
| ST3M571-4-18 | J M Precision Inc (USA) |
| ST3M571-4-18 PRIMARY | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| ST3M571-4-18 | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| ST3M571-4-18 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| ST3M571-4-18 | Heartland Precision Fasteners Inc (USA) |
| ST3M571-4-18 | Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries (USA) |
| ST3M571-4-18 PRIMARY | Hi-Shear Corporation (USA) |
| ST3M571-4-18 PRIMARY | Fastener Innovation Technology, Inc. Dba F I T (USA) |
| ST3M571-4-18 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| ST3M571-4-18 | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| GS1030-4-18 | B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace (USA) |
| 11831-4-18 | Reid Products Inc. Dba Reid Products Inc (USA) |
| Reference | Meaning |
|---|---|
| MB84-4-18 | 5/9 Secondary reference Hi-Shear Corporation |
| S11-1059-4-18 | 5/9 Secondary reference Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries |
| VS3060-4-18 | 5/9 Secondary reference U.S. Government activity |
| S371-4-18 | 5/9 Secondary reference U.S. Government activity |
| VS3060-4-18 | C/1 Advisory reference — outside the item-of-supply concept Howmet Global Fastening Systems Inc |
| ST3M571-4-18 | 5/2 Secondary reference U.S. Government activity |
| 74328-4-18 | 5/9 Secondary reference U.S. Government activity |
| AIC752-4-18 | 5/9 Secondary reference Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company |
| BM3326-4-18 | 5/9 Secondary reference U.S. Government activity |
| ST3M571-4-18 | 5/2 Secondary reference U.S. Government activity |
| VAL23033-4-18 | 5/9 Secondary reference Valley-Todeco, Inc. Dba Arconic Fastening Systems |
| 74328-4-18 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| ST3M571-4-18 | 7/2 Vendor item drawing reference The Boeing Company Div Defense |
NSN 5306-01-027-5249 is a Bolt,close Tolerance, manufactured by Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc, classified under FSC 5306, Bolts. Status: active.
NSN 5306-01-027-5249 has 13 manufacturer part numbers on file: ST3M571-4-18 (Saturn Fasteners Inc), ST3M571-4-18 (J M Precision Inc), ST3M571-4-18 (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), ST3M571-4-18 (Valley-Todeco, Inc. Dba Arconic Fastening Systems), ST3M571-4-18 (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners) and 8 more.
Key specifications for ST3M571-4-18: Extended Washer Thickness: 0.059 INCHES MINIMUM AND 0.079 INCHES MAXIMUM IN; Head Height: 0.290 INCHES MINIMUM AND 0.310 INCHES MAXIMUM IN; Fastener Length: 1.578 INCHES MINIMUM AND 1.608 INCHES MAXIMUM IN; Extended Washer Diameter: 0.428 INCHES MINIMUM AND 0.438 INCHES MAXIMUM IN. 17 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.