The Screw,close Tolerance, cataloged under National Stock Number 5305-01-170-4571, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company. Government technical data includes 20 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through both NSN and commercial part number lookups. 4 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-170-4571 |
| Primary Part Number | BACB30LK2-4 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company |
| 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 | 0.105 INCHES MINIMUM AND 0.115 INCHES MAXIMUM IN |
| Fastener Length | 0.580 INCHES MINIMUM AND 0.610 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-416 TYPE 2 CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.320 INCHES MINIMUM AND 0.370 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5737 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.164 INCHES IN |
| Head Style | PAN |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.240 INCHES MINIMUM AND 0.260 INCHES MAXIMUM IN |
| Grip Diameter | 0.1625 INCHES MINIMUM AND 0.1635 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM AND CHROMATE OVERALL |
| Internal Drive Style | CROSS RECESS TYPE 1 |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 32 |
| Material | IRON ALLOY 660 OVERALL |
| Thread Series Designator | UNJC |
| Head Diameter | 0.306 INCHES MINIMUM AND 0.322 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 |
|---|---|
| BACB30LK2-4 PRIMARY | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| BACB30LK2-4 PRIMARY | Huck International, Inc (USA) |
| BACB30LK2-4 PRIMARY | Howmet Global Fastening Systems Inc (USA) |
| BACB30LK2-4 PRIMARY | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| BACB30LK2-4 PRIMARY | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| BACB30LK2-4 PRIMARY | Federal Manufacturing Corp (USA) |
| Reference | Meaning |
|---|---|
| BACB30LK2-4 | 5/9 Secondary reference U.S. Government activity |
| BACB30LK2-4 | 5/2 Secondary reference U.S. Government activity |
| BACB30LK2-4 | 3/2 Design control — primary reference U.S. Government activity |
| BACB30LK2-4 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-170-4571 is a Screw,close Tolerance, manufactured by Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-170-4571 has 6 manufacturer part numbers on file: BACB30LK2-4 (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), BACB30LK2-4 (Huck International, Inc), BACB30LK2-4 (Howmet Global Fastening Systems Inc), BACB30LK2-4 (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), BACB30LK2-4 (Valley-Todeco, Inc. Dba Arconic Fastening Systems) and 1 more.
1 possible match (shared part number, not a government interchangeability claim): 5305-01-684-5505. Verify interchangeability with system specifications before substitution.
Key specifications for BACB30LK2-4: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Surface Finish: 32.0 MICROINCHES BEARING SURFACE OF HEAD; Head Height: 0.105 INCHES MINIMUM AND 0.115 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.