The Screw,close Tolerance, cataloged under National Stock Number 5305-01-027-4661, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Hi-Shear Corporation. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 14 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 7 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-027-4661 |
| Primary Part Number | HT4020-4-8A |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Hi-Shear Corporation |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Head Height | 0.071 INCHES MINIMUM AND 0.073 INCHES MAXIMUM IN |
| Fastener Length | 0.952 INCHES MINIMUM AND 0.999 INCHES MAXIMUM IN |
| Thread Length | 0.442 INCHES MINIMUM AND 0.509 INCHES MAXIMUM IN |
| Material Document and Classification | AMS 5629 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | FLAT COUNTERSUNK UNDERCUT |
| Thread Direction | RIGHT-HAND |
| Grip Length | 0.490 INCHES MINIMUM AND 0.510 INCHES MAXIMUM IN |
| Grip Diameter | 0.2490 INCHES MINIMUM AND 0.2495 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Internal Drive Style | HIGH-TORQUE |
| Countersink Angle | 100.0 DEGREES NOMINAL |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Material | STEEL COMP XM-13 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.502 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 |
|---|---|
| HT4020-4-8A | Huck International, Inc (USA) |
| ST3M652C4-8A | Fastener Innovation Technology, Inc. Dba F I T (USA) |
| ST3M652C4-8A | Valley-Todeco, Inc. Dba Arconic Fastening Systems (USA) |
| HT4020-4-8A | Sps Technologies Ltd, Tj Brooks Division (GBR) |
| HT4020-4-8A | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| HT4020-4-8A | Howmet Global Fastening Systems Inc (USA) |
| HT4020-4-8A | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| HT4020-4-8A | Sps Technologies, Llc Dba PB Fasteners (USA) |
| 11925C4-8A | Reid Products Inc. Dba Reid Products Inc (USA) |
| HT4020-4-8A PRIMARY | Hi-Shear Corporation (USA) |
| HT4020-4-8A PRIMARY | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| ST3M652C4-8A | Heartland Precision Fasteners Inc (USA) |
| ST3M652C4-8A | Houston Precision Fasteners I Lp (USA) |
| WC4020-4-8A | West Coast Aerospace, Inc. (USA) |
| Reference | Meaning |
|---|---|
| CHT4020-4-8A | C/1 Advisory reference — outside the item-of-supply concept Deutsch Co the |
| HT4020-4-8A | 3/2 Design control — primary reference U.S. Government activity |
| CHT4020-4-8A | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| CHT4020-4-8A | C/1 Advisory reference — outside the item-of-supply concept U.S. Government activity |
| HT4020-4-8A | 5/9 Secondary reference U.S. Government activity |
| HT4020-4-8A | 5/9 Secondary reference U.S. Government activity |
| ST3M652C4-8A | 7/2 Vendor item drawing reference The Boeing Company Div Defense |
NSN 5305-01-027-4661 is a Screw,close Tolerance, manufactured by Hi-Shear Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-027-4661 has 14 manufacturer part numbers on file: HT4020-4-8A (Huck International, Inc), ST3M652C4-8A (Fastener Innovation Technology, Inc. Dba F I T), ST3M652C4-8A (Valley-Todeco, Inc. Dba Arconic Fastening Systems), HT4020-4-8A (Sps Technologies Ltd, Tj Brooks Division), HT4020-4-8A (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company) and 9 more.
Key specifications for HT4020-4-8A: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Head Height: 0.071 INCHES MINIMUM AND 0.073 INCHES MAXIMUM IN; Fastener Length: 0.952 INCHES MINIMUM AND 0.999 INCHES MAXIMUM IN. 19 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.