The Washer,flat, cataloged under National Stock Number 5310-01-421-9920, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Syn-Tech System, Inc.. Government technical data includes 11 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-421-9920 |
| Primary Part Number | 921C0107 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Syn-Tech System, Inc. |
| Status | ACTIVE |
| Surface Treatment Document and Classification | ASTM B633 TYPE 2 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Overall Diameter | 1.000 INCHES NOMINAL IN |
| Hardness Rating | 45.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM |
| Material Document and Classification | QQ-S-624 4340 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | ZINC AND CHROMATE OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL COMP E4340 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.328 INCHES NOMINAL IN |
| Thickness | 0.125 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 |
|---|---|
| 921C0107 PRIMARY | Syn-Tech System, Inc. (USA) |
NSN 5310-01-421-9920 is a Washer,flat, manufactured by Syn-Tech System, Inc., classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-421-9920 has 1 manufacturer part number on file: 921C0107 (Syn-Tech System, Inc.).
Key specifications for 921C0107: Surface Treatment Document and Classification: ASTM B633 TYPE 2 ASSN STD SINGLE TREATMENT RESPONSE OVERALL; Overall Diameter: 1.000 INCHES NOMINAL IN; Hardness Rating: 45.0 ROCKWELL C MINIMUM AND 50.0 ROCKWELL C MAXIMUM; Material Document and Classification: QQ-S-624 4340 FED SPEC SINGLE MATERIAL RESPONSE OVERALL. 11 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.