The Bolt,close Tolerance, cataloged under National Stock Number 5306-01-030-4657, is classified within Federal Supply Class 5306 (Bolts) of the Hardware and Abrasives group. The manufacturer of record is Huck International, Inc. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 19 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 8 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5306-01-030-4657 |
| Primary Part Number | S371-4D27 |
| Item Name | Bolt,close Tolerance |
| FSC / FSG | 5306 / 53 — Bolts |
| Manufacturer | Huck International, 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 | 2.141 INCHES MINIMUM AND 2.171 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 |
| Shank Unthreaded Hole Diameter | 0.076 INCHES MINIMUM AND 0.081 INCHES MAXIMUM FIRST HOLE 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 | 1.678 INCHES MINIMUM AND 1.698 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) |
| Distance From Head Largest Bearing Surface to Shank Hole Center | 1.949 INCHES MINIMUM AND 1.989 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 |
|---|---|
| VAL23033-4D27 | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| SLB253-4D27 | B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace (USA) |
| S371-4D27 PRIMARY | Huck International, Inc (USA) |
| VS3060-4D27 PRIMARY | Howmet Global Fastening Systems Inc (USA) |
| S11-1059-4D27 | Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries (USA) |
| SLB253-4D27 | Space-Lok, Inc. Dba Space-Lok Inc Div Space-Lok (USA) |
| AIC752-4D27 | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| ST3M571-4D27 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| SLB253-4D27 | Fastener Innovation Technology, Inc. Dba F I T (USA) |
| MB84-4D27 | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| GS1030-4D27 | B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace (USA) |
| PBF23T4PD27 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| BM3326-4D27 PRIMARY | Huck International, Inc (USA) |
| ST3M571-4D27 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| SLB253-4D27 | Saturn Fasteners Inc (USA) |
| MB84-4D27 | Hi-Shear Corporation (USA) |
| SLB253-4D27 | Heartland Precision Fasteners Inc (USA) |
| SLB253-4D27 | Houston Precision Fasteners I Lp (USA) |
| SLB253-4D27 | Reid Products Inc. Dba Reid Products Inc (USA) |
| Reference | Meaning |
|---|---|
| BM3326-4D27 | 5/9 Secondary reference U.S. Government activity |
| 74328-4D27 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| ST3M571-4D27 | 5/9 Secondary reference J M Precision Inc |
| ST3M571-4D27 | 5/2 Secondary reference U.S. Government activity |
| 74328-4D27 | 5/2 Secondary reference U.S. Government activity |
| ST3M571-4D27 | 7/2 Vendor item drawing reference The Boeing Company Div Defense |
| VS3060-4D27 | 5/9 Secondary reference U.S. Government activity |
| S371-4D27 | 5/9 Secondary reference U.S. Government activity |
NSN 5306-01-030-4657 is a Bolt,close Tolerance, manufactured by Huck International, Inc, classified under FSC 5306, Bolts. Status: active.
NSN 5306-01-030-4657 has 19 manufacturer part numbers on file: VAL23033-4D27 (Valley-Todeco, Inc. Dba Arconic Fastening Systems), SLB253-4D27 (B & B Specialties Inc Dba Gs Aerospace Div Gs Aerospace), S371-4D27 (Huck International, Inc), VS3060-4D27 (Howmet Global Fastening Systems Inc), S11-1059-4D27 (Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries) and 14 more.
Key specifications for S371-4D27: 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: 2.141 INCHES MINIMUM AND 2.171 INCHES MAXIMUM IN; Extended Washer Diameter: 0.428 INCHES MINIMUM AND 0.438 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.