The Screw,close Tolerance, cataloged under National Stock Number 5305-01-021-3759, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Valley-Todeco, Inc. Dba Arconic Fastening Systems. Government technical data includes 18 specifications, cited from the U.S. Government catalog. The record lists 6 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through both NSN and commercial part number lookups. 8 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog.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 | 5305-01-021-3759 |
| Primary Part Number | BACB30LU4-3 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Valley-Todeco, Inc. Dba Arconic Fastening Systems |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Fastener Length | 0.598 INCHES MINIMUM AND 0.628 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416,TY 2,CL 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.400 INCHES MINIMUM AND 0.450 INCHES MAXIMUM IN |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.178 INCHES MINIMUM AND 0.198 INCHES MAXIMUM IN |
| Grip Diameter | 0.2485 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Internal Drive Style | CROSS RECESS TYPE 1 |
| Countersink Angle | 100.0 DEGREES NOMINAL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP E4340 OR STEEL COMP 4340 OR STEEL COMP 8740 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.455 INCHES MINIMUM AND 0.510 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 |
|---|---|
| BACB30LU4-3 PRIMARY | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| BACB30LU4-3 PRIMARY | Federal Manufacturing Corp (USA) |
| BACB30LU4-3 PRIMARY | Howmet Global Fastening Systems Inc (USA) |
| BACB30LU4-3 PRIMARY | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| BACB30LU4-3 PRIMARY | Huck International, Inc (USA) |
| BACB30LU4-3 PRIMARY | Howmet Global Fastening Systems Inc Div City of Industry Operations (USA) |
| Reference | Meaning |
|---|---|
| BACB30LU4-3 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| BACB30LU4-3 | 5/9 Secondary reference U.S. Government activity |
| BACB30LU4-3 | 5/9 Secondary reference U.S. Government activity |
| BACB30LU4-3 | 3/2 Design control — primary reference U.S. Government activity |
| BACB30LU4-3 | 5/9 Secondary reference Sonic Industries, Inc. Dba Sonic Industries Inc Div Sonic Industries |
| BACB30LU403 | 5/9 Secondary reference Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company |
| BACB30LU4-3 | 5/9 Secondary reference Sps Technologies Llc Dba PB Fasteners Div PB Fasteners |
| BACB30LU4-3 | 7/2 Vendor item drawing reference U.S. Government activity |
NSN 5305-01-021-3759 is a Screw,close Tolerance, manufactured by Valley-Todeco, Inc. Dba Arconic Fastening Systems, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-021-3759 has 6 manufacturer part numbers on file: BACB30LU4-3 (Valley-Todeco, Inc. Dba Arconic Fastening Systems), BACB30LU4-3 (Federal Manufacturing Corp), BACB30LU4-3 (Howmet Global Fastening Systems Inc), BACB30LU4-3 (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), BACB30LU4-3 (Huck International, Inc) and 1 more.
Key specifications for BACB30LU4-3: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Fastener Length: 0.598 INCHES MINIMUM AND 0.628 INCHES MAXIMUM IN; Surface Treatment Document and Classification: QQ-P-416,TY 2,CL 3 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.