The Washer,key, cataloged under National Stock Number 5310-00-756-4403, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Ontic Engineering & Manufacturing, Inc Dba Ontic Us. Government technical data includes 14 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through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-00-756-4403 |
| Primary Part Number | 643669 |
| Item Name | Washer,key |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Ontic Engineering & Manufacturing, Inc Dba Ontic Us |
| Status | ACTIVE |
| Distance From Centerline to Inside of Prebent Key | 0.243 INCHES NOMINAL IN |
| Split Key Length | 0.125 INCHES NOMINAL IN |
| External Prebent Key Length | 0.062 INCHES NOMINAL IN |
| Overall Distance Including Keys | 0.583 INCHES NOMINAL IN |
| Style Designator | KEY |
| Outside Diameter | 0.436 INCHES NOMINAL IN |
| External Tapered Key Width | 0.142 INCHES NOMINAL IN |
| Material Thickness | 0.018 INCHES NOMINAL IN |
| External Key Quantity | 1 |
| Surface Treatment | PASSIVATE OVERALL |
| External Prebent Key Width | 0.200 INCHES NOMINAL IN |
| Material | STEEL CORROSION RESISTING OVERALL |
| Angle Between External Keys | 45.0 DEGREES NOMINAL |
| Hole Diameter | 0.266 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 |
|---|---|
| 643669 PRIMARY | Ontic Engineering & Manufacturing, Inc Dba Ontic Us (USA) |
| Reference | Meaning |
|---|---|
| 643669 | 5/2 Secondary reference U.S. Government activity |
NSN 5310-00-756-4403 is a Washer,key, manufactured by Ontic Engineering & Manufacturing, Inc Dba Ontic Us, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-756-4403 has 1 manufacturer part number on file: 643669 (Ontic Engineering & Manufacturing, Inc Dba Ontic Us).
Key specifications for 643669: Distance From Centerline to Inside of Prebent Key: 0.243 INCHES NOMINAL IN; Split Key Length: 0.125 INCHES NOMINAL IN; External Prebent Key Length: 0.062 INCHES NOMINAL IN; Overall Distance Including Keys: 0.583 INCHES NOMINAL 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.