The Screw,close Tolerance, cataloged under National Stock Number 5305-01-243-0758, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is The Boeing Company Div Defense. Government technical data includes 21 specifications, cited from the U.S. Government catalog. The record lists 8 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-243-0758 |
| Primary Part Number | ST3M652C6-21A |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | The Boeing Company Div Defense |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Surface Finish | 32.0 MICROINCHES BEARING SURFACE OF HEAD |
| Head Height | 0.1147 INCHES MINIMUM AND 0.1167 INCHES MAXIMUM IN |
| Fastener Length | 1.937 INCHES MINIMUM AND 1.984 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.615 INCHES MINIMUM AND 0.682 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5629 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.375 INCHES IN |
| Head Style | FLAT COUNTERSUNK UNDERCUT |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN |
| Grip Diameter | 0.3740 INCHES MINIMUM AND 0.3745 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Internal Drive Style | HIGH-TORQUE |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 24 |
| Material | STEEL COMP XM-13 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.7556 INCHES MINIMUM AND 0.7604 INCHES MAXIMUM 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 |
|---|---|
| ST3M652C6-21A | Huck International, Inc (USA) |
| ST3M652C6-21A | Reid Products Inc. Dba Reid Products Inc (USA) |
| HT4020-6-21A | Howmet Global Fastening Systems Inc (USA) |
| ST3M652C6-21A PRIMARY | The Boeing Company Div Defense (USA) |
| HT4020-6-21A | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| ST3M652C6-21A | West Coast Aerospace, Inc. (USA) |
| ST3M652C6-21A | Fastener Innovation Technology, Inc. Dba F I T (USA) |
| HT4020-6-21A | Hi-Shear Corporation (USA) |
| Reference | Meaning |
|---|---|
| HT4020-6-21A | 5/9 Secondary reference U.S. Government activity |
| 10113579 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
| HT4020-6-21A | 5/9 Secondary reference U.S. Government activity |
| HT4020-6-21A | 5/2 Secondary reference U.S. Government activity |
NSN 5305-01-243-0758 is a Screw,close Tolerance, manufactured by The Boeing Company Div Defense, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-243-0758 has 8 manufacturer part numbers on file: ST3M652C6-21A (Huck International, Inc), ST3M652C6-21A (Reid Products Inc. Dba Reid Products Inc), HT4020-6-21A (Howmet Global Fastening Systems Inc), ST3M652C6-21A (The Boeing Company Div Defense), HT4020-6-21A (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc) and 3 more.
Key specifications for ST3M652C6-21A: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Surface Finish: 32.0 MICROINCHES BEARING SURFACE OF HEAD; Head Height: 0.1147 INCHES MINIMUM AND 0.1167 INCHES MAXIMUM IN. 21 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.