The Screw,close Tolerance, cataloged under National Stock Number 5305-01-591-0368, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies, Llc Dba PB Fasteners. Government technical data includes 21 specifications, cited from the U.S. Government catalog. The record lists 15 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-591-0368 |
| Primary Part Number | HT4027-6-6 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Sps Technologies, Llc Dba PB Fasteners |
| Status | ACTIVE |
| Head Height | 0.018 INCHES MAXIMUM IN |
| Point Length | 0.052 INCHES NOMINAL IN |
| Fastener Length | 1.001 INCHES MINIMUM AND 1.031 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | AMS 2700 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.641 INCHES NOMINAL IN |
| Material Document and Classification | AMS 5662 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Point Chamfer Angle | 45.0 DEGREES NOMINAL |
| Nominal Thread Diameter | 0.375 INCHES IN |
| Head Style | FILLISTER COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Point Style | FLAT |
| Grip Length | 0.375 INCHES NOMINAL IN |
| Grip Diameter | 0.374 INCHES MINIMUM AND 0.375 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 | NICKEL ALLOY 718 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.510 INCHES MINIMUM AND 0.564 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 |
|---|---|
| HT4027-6-6 | Howmet Global Fastening Systems Inc (USA) |
| ST3M557-6-6 | Saturn Fasteners Inc (USA) |
| ST3M557-6-6 | Linread Ltd (GBR) |
| HT4027-6-6 PRIMARY | Sps Technologies, Llc Dba PB Fasteners (USA) |
| ST3M557-6-6 | Houston Precision Fasteners I Lp (USA) |
| HT4027-6-6 PRIMARY | Hi-Shear Corporation (USA) |
| ST3M557-6-6 | Heartland Precision Fasteners Inc (USA) |
| HT4027-6-6 PRIMARY | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| ST3M557-6-6 | Camcar Llc Div Camcar Llc (USA) |
| WC4027-6-6 | West Coast Aerospace, Inc. (USA) |
| 11923-6-6 | Reid Products Inc. Dba Reid Products Inc (USA) |
| HT4027-6-6 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| ST3M557-6-6 | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| HT4027-6-6 PRIMARY | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| HT4027-6-6 | Huck International, Inc (USA) |
| Reference | Meaning |
|---|---|
| ST3M557-6-6 | 7/2 Vendor item drawing reference The Boeing Company Div Defense |
| HT4027-6-6 | 5/2 Secondary reference U.S. Government activity |
| HT4027-6-6 | 5/2 Secondary reference U.S. Government activity |
NSN 5305-01-591-0368 is a Screw,close Tolerance, manufactured by Sps Technologies, Llc Dba PB Fasteners, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-591-0368 has 15 manufacturer part numbers on file: HT4027-6-6 (Howmet Global Fastening Systems Inc), ST3M557-6-6 (Saturn Fasteners Inc), ST3M557-6-6 (Linread Ltd), HT4027-6-6 (Sps Technologies, Llc Dba PB Fasteners), ST3M557-6-6 (Houston Precision Fasteners I Lp) and 10 more.
Key specifications for HT4027-6-6: Head Height: 0.018 INCHES MAXIMUM IN; Point Length: 0.052 INCHES NOMINAL IN; Fastener Length: 1.001 INCHES MINIMUM AND 1.031 INCHES MAXIMUM IN; Surface Treatment Document and Classification: AMS 2700 ASSN STD SINGLE TREATMENT RESPONSE OVERALL. 21 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.