The Screw,cap,socket Head, cataloged under National Stock Number 5305-01-175-6938, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Howmet Global Fastening Systems Inc. Div Tridair Products. Government technical data includes 18 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-175-6938 |
| Primary Part Number | CA21189-4-6HS |
| Item Name | Screw,cap,socket Head |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Howmet Global Fastening Systems Inc. Div Tridair Products |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Width Across Flats | 0.1562 INCHES MINIMUM AND 0.1587 INCHES MAXIMUM IN |
| Fastener Length | 1.047 INCHES MINIMUM AND 1.067 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.477 INCHES MINIMUM AND 0.636 INCHES MAXIMUM IN |
| Material Document and Classification | AMS5737 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Surface Treatment | PASSIVATE OVERALL |
| Minimum Tensile Strength | 160000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HEXAGON |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | IRON ALLOY 660 OVERALL |
| Thread Series Designator | UNF |
| Head Diameter | 0.360 INCHES MINIMUM AND 0.404 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 |
|---|---|
| CA21189-4-6HS | Howmet Global Fastening Systems Inc. Div Tridair Products (USA) |
| Reference | Meaning |
|---|---|
| BACF34L4BS6HS | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-175-6938 is a Screw,cap,socket Head, manufactured by Howmet Global Fastening Systems Inc. Div Tridair Products, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-175-6938 has 1 manufacturer part number on file: CA21189-4-6HS (Howmet Global Fastening Systems Inc. Div Tridair Products).
Key specifications for CA21189-4-6HS: Surface Finish: 32.0 MICROINCHES GRIP; Width Across Flats: 0.1562 INCHES MINIMUM AND 0.1587 INCHES MAXIMUM IN; Fastener Length: 1.047 INCHES MINIMUM AND 1.067 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL. 18 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.