The Washer,recessed, cataloged under National Stock Number 5310-00-253-7651, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp. Government technical data includes 12 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 | 5310-00-253-7651 |
| Primary Part Number | S1620-64175-4 |
| Item Name | Washer,recessed |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp |
| Status | ACTIVE |
| Surface Finish | 100.0 MICROINCHES ALL SURFACES |
| Surface Treatment Document and Classification | SS-8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL |
| Hardness Rating | 26.0 ROCKWELL C MINIMUM AND 33.0 ROCKWELL C MAXIMUM |
| Style Designator | RECESSED |
| Material Document and Classification | MIL-S-18732 MIL SPEC SINGLE MATERIAL RESPONSE OVERALL |
| Outside Diameter | 0.625 INCHES NOMINAL IN |
| Recess Depth | 0.125 INCHES NOMINAL IN |
| Material Thickness | 0.131 INCHES MINIMUM AND 0.136 INCHES MAXIMUM IN |
| Surface Treatment | PASSIVATE OVERALL |
| Minimum Tensile Strength | 125000 POUNDS PER SQUARE INCH LBS |
| Material | STEEL CORROSION RESISTING OVERALL |
| Hole Diameter | 0.375 INCHES MINIMUM AND 0.380 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 |
|---|---|
| S1620-64175-4 PRIMARY | Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp (USA) |
NSN 5310-00-253-7651 is a Washer,recessed, manufactured by Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-00-253-7651 has 1 manufacturer part number on file: S1620-64175-4 (Sikorsky Aircraft Corporation Dba Sikorsky Aircraft Corp).
Key specifications for S1620-64175-4: Surface Finish: 100.0 MICROINCHES ALL SURFACES; Overall Height: 0.188 INCHES NOMINAL IN; Surface Treatment Document and Classification: SS-8435,FSCM 78286 MFR REF SINGLE TREATMENT RESPONSE OVERALL; Hardness Rating: 26.0 ROCKWELL C MINIMUM AND 33.0 ROCKWELL C MAXIMUM. 12 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.