The Screw,close Tolerance, cataloged under National Stock Number 5305-01-136-7151, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Northrop Grumman Systems Corporation. Government technical data includes 20 specifications, cited from the U.S. Government catalog. The record lists 3 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-136-7151 |
| Primary Part Number | GB510BC4-18 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Northrop Grumman Systems Corporation |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Fastener Length | 1.521 INCHES MINIMUM AND 1.568 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | NAS 672 ASSN STD 1ST TREATMENT RESPONSE OR MIL-C-8837 TY 2 CL 2 MIL SPEC 2ND TREATMENT RESPONSE OVERALL |
| Thread Length | 0.386 INCHES MINIMUM AND 0.453 INCHES MAXIMUM IN |
| Hardness Rating | 46.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM OVERALL |
| Material Document and Classification | AMS 6487 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.115 INCHES MINIMUM AND 1.135 INCHES MAXIMUM IN |
| Grip Diameter | 0.2483 INCHES MINIMUM AND 0.2492 INCHES MAXIMUM IN |
| Surface Treatment | CADMIUM OR CADMIUM AND CHROMATE OVERALL |
| Minimum Tensile Strength | 220000 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | HIGH-TORQUE |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP H11 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.447 INCHES MINIMUM AND 0.507 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 |
|---|---|
| GB510BC4-18 PRIMARY | Northrop Grumman Systems Corporation (USA) |
| GB510BC4-18 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| GB510BC4-18 | Huck International, Inc (USA) |
| Reference | Meaning |
|---|---|
| H148-4-18 | 5/9 Secondary reference U.S. Government activity |
| GB510BC4-18 | 5/2 Secondary reference U.S. Government activity |
| HT8171-4-18 | 5/9 Secondary reference U.S. Government activity |
| 106706H-4-A18 | 5/9 Secondary reference U.S. Government activity |
| 106706H-4-A18 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| H148-4-18 | C/1 Advisory reference — outside the item-of-supply concept Huck International, Inc |
NSN 5305-01-136-7151 is a Screw,close Tolerance, manufactured by Northrop Grumman Systems Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-136-7151 has 3 manufacturer part numbers on file: GB510BC4-18 (Northrop Grumman Systems Corporation), GB510BC4-18 (Sps Technologies, Llc Dba PB Fasteners), GB510BC4-18 (Huck International, Inc).
Key specifications for GB510BC4-18: Surface Finish: 32.0 MICROINCHES GRIP; Fastener Length: 1.521 INCHES MINIMUM AND 1.568 INCHES MAXIMUM IN; Surface Treatment Document and Classification: NAS 672 ASSN STD 1ST TREATMENT RESPONSE OR MIL-C-8837 TY 2 CL 2 MIL SPEC 2ND TREATMENT RESPONSE OVERALL; Thread Length: 0.386 INCHES MINIMUM AND 0.453 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.