The Screw,machine, cataloged under National Stock Number 5305-00-993-8730, 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 14 specifications, cited from the U.S. Government catalog. The record lists 5 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 5 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-00-993-8730 |
| Primary Part Number | 51B221-16 |
| Item Name | Screw,machine |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Hi-Shear Corporation |
| Status | ACTIVE |
| Head Height | 0.109 INCHES NOMINAL IN |
| Screw Surface Treatment | CADMIUM |
| Fastener Length | 1.276 INCHES NOMINAL IN |
| Thread Length | 0.276 INCHES MINIMUM IN |
| Nominal Thread Diameter | 0.190 INCHES IN |
| Head Style | BUTTON |
| Thread Direction | RIGHT-HAND |
| Screw Material | STEEL |
| Minimum Tensile Strength | 180 POUNDS PER SQUARE INCH LBS |
| Internal Drive Style | TORQUE SET |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 32 |
| Thread Series Designator | UNF |
| Head Diameter | 0.390 INCHES NOMINAL 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 |
|---|---|
| 51B221-16 | Hi-Shear Corporation (USA) |
| 51B221-16 | Howmet Global Fastening Systems Inc (USA) |
| 51B221-16 | Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company (USA) |
| 51B221-16 | Sps Technologies Llc Dba PB Fasteners Div PB Fasteners (USA) |
| 51B221-16 | Huck International, Inc (USA) |
| Reference | Meaning |
|---|---|
| 51B221-16 | 3/9 Design control — primary reference Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems |
| 51B221-16 | 5/2 Secondary reference U.S. Government activity |
| 51B221-16 | 5/9 Secondary reference Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc |
| 51B221-16 | C/1 Advisory reference — outside the item-of-supply concept Northrop Grumman Technical Services, Inc. Dba Defense Systems Sector |
| 51B221-16 | 5/2 Secondary reference U.S. Government activity |
NSN 5305-00-993-8730 is a Screw,machine, manufactured by Hi-Shear Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-00-993-8730 has 5 manufacturer part numbers on file: 51B221-16 (Hi-Shear Corporation), 51B221-16 (Howmet Global Fastening Systems Inc), 51B221-16 (Sps Technologies, Llc Dba Air Industries Company Div Air Industries Company), 51B221-16 (Sps Technologies Llc Dba PB Fasteners Div PB Fasteners), 51B221-16 (Huck International, Inc).
Key specifications for 51B221-16: Head Height: 0.109 INCHES NOMINAL IN; Screw Surface Treatment: CADMIUM; Fastener Length: 1.276 INCHES NOMINAL IN; Thread Length: 0.276 INCHES MINIMUM IN. 14 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.