The Screw,close Tolerance, cataloged under National Stock Number 5305-01-128-5124, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is West Coast Aerospace, Inc.. Government technical data includes 20 specifications, cited from the U.S. Government catalog. The record lists 7 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-128-5124 |
| Primary Part Number | WC4020-6-20A |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | West Coast Aerospace, Inc. |
| 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 | 0.115 INCHES MINIMUM AND 0.117 INCHES MAXIMUM IN |
| Fastener Length | 1.875 INCHES MINIMUM AND 1.922 INCHES MAXIMUM IN |
| Thread Length | 0.615 INCHES MINIMUM AND 0.682 INCHES MAXIMUM IN |
| Material Document and Classification | AMS5629 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.375 INCHES IN |
| Head Style | FLAT COUNTERSUNK UNDERCUT |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.240 INCHES MINIMUM AND 1.260 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 | 0.756 INCHES MINIMUM AND 0.760 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 |
|---|---|
| ST3M652C6-20A | Fastener Innovation Technology, Inc. Dba F I T (USA) |
| HT4020-6-20A | Hi-Shear Corporation (USA) |
| 119256-20A | Reid Products Inc. Dba Reid Products Inc (USA) |
| WC4020-6-20A PRIMARY | West Coast Aerospace, Inc. (USA) |
| HT4020-6-20A | Howmet Global Fastening Systems Inc (USA) |
| HT4020-6-20A | Huck International, Inc (USA) |
| 11925C6-20A | Reid Products Inc. Dba Reid Products Inc (USA) |
| Reference | Meaning |
|---|---|
| 10115172 | 6/9 Informative reference only Nimikkeistokeskus Ncb Finland |
| ST3M6526-20A | 5/9 Secondary reference Fastener Innovation Technology, Inc. Dba F I T |
| HT4020-6-20A | 3/2 Design control — primary reference U.S. Government activity |
| HT4020-6-20A | 5/9 Secondary reference Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc |
| ST3M652C6-20A | 7/2 Vendor item drawing reference The Boeing Company Div Defense |
NSN 5305-01-128-5124 is a Screw,close Tolerance, manufactured by West Coast Aerospace, Inc., classified under FSC 5305, Screws. Status: active.
NSN 5305-01-128-5124 has 7 manufacturer part numbers on file: ST3M652C6-20A (Fastener Innovation Technology, Inc. Dba F I T), HT4020-6-20A (Hi-Shear Corporation), 119256-20A (Reid Products Inc. Dba Reid Products Inc), WC4020-6-20A (West Coast Aerospace, Inc.), HT4020-6-20A (Howmet Global Fastening Systems Inc) and 2 more.
Key specifications for WC4020-6-20A: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Surface Finish: 32.0 MICROINCHES BEARING SURFACE OF HEAD; Head Height: 0.115 INCHES MINIMUM AND 0.117 INCHES MAXIMUM IN. 20 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.