The Washer,flat, cataloged under National Stock Number 5310-01-566-9850, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is U S Army Tank Automotive Command Amsta-Im-Mm. 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through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-566-9850 |
| Primary Part Number | 12387327-28 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | U S Army Tank Automotive Command Amsta-Im-Mm |
| Status | ACTIVE |
| Surface Treatment Document and Classification | MIL-STD-171, 1.9.2.2 MIL STD SINGLE TREATMENT RESPONSE AND ASTM B633, TY II, CL 2 ASSN STD SINGLE TREATMENT RESPONSE OVERALL |
| Overall Diameter | 1.990 INCHES MINIMUM AND 2.010 INCHES MAXIMUM IN |
| Hardness Rating | 33.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM |
| Material Document and Classification | A829 ASSN STD 1ST MATERIAL RESPONSE OR A322 ASSN STD 1ST MATERIAL RESPONSE OR A331 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6350 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6351 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6345 ASSN STD 1ST MATERIAL RESPONSE OR A829 ASSN STD 2ND MATERIAL RESPONSE OR A322 ASSN STD 2ND MATERIAL RESPONSE OR A331 ASSN STD 2ND MATERIAL RESPONSE OR A829 ASSN STD 3RD MATERIAL RESPONSE OR A322 ASSN STD 3RD MATERIAL RESPONSE OR A331 ASSN STD 3RD MATERIAL RESPONSE OR A322 ASSN STD 4TH MATERIAL RESPONSE OR A331 ASSN STD 4TH MATERIAL RESPONSE OVERALL |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | ZINC OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL COMP 4130 OR STEEL COMP 4140 OR STEEL COMP 8640 OR STEEL COMP 8740 OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.521 INCHES MINIMUM AND 0.541 INCHES MAXIMUM IN |
| Thickness | 0.202 INCHES MINIMUM AND 0.216 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 |
|---|---|
| 12387327-28 PRIMARY | U S Army Tank Automotive Command Amsta-Im-Mm (USA) |
| Reference | Meaning |
|---|---|
| 12387327-28 | 5/9 Secondary reference U.S. Government activity |
| 12387327 | D/9 Drawing number reference only U S Army Tank Automotive Command Amsta-Im-Mm |
| 10910174 | D/9 Drawing number reference only U S Army Tank Automotive Command Amsta-Im-Mm |
NSN 5310-01-566-9850 is a Washer,flat, manufactured by U S Army Tank Automotive Command Amsta-Im-Mm, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-566-9850 has 1 manufacturer part number on file: 12387327-28 (U S Army Tank Automotive Command Amsta-Im-Mm).
Key specifications for 12387327-28: Surface Treatment Document and Classification: MIL-STD-171, 1.9.2.2 MIL STD SINGLE TREATMENT RESPONSE AND ASTM B633, TY II, CL 2 ASSN STD SINGLE TREATMENT RESPONSE OVERALL; Overall Diameter: 1.990 INCHES MINIMUM AND 2.010 INCHES MAXIMUM IN; Hardness Rating: 33.0 ROCKWELL C MINIMUM AND 38.0 ROCKWELL C MAXIMUM; Material Document and Classification: A829 ASSN STD 1ST MATERIAL RESPONSE OR A322 ASSN STD 1ST MATERIAL RESPONSE OR A331 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6350 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6351 ASSN STD 1ST MATERIAL RESPONSE OR AMS 6345 ASSN STD 1ST MATERIAL RESPONSE OR A829 ASSN STD 2ND MATERIAL RESPONSE OR A322 ASSN STD 2ND MATERIAL RESPONSE OR A331 ASSN STD 2ND MATERIAL RESPONSE OR A829 ASSN STD 3RD MATERIAL RESPONSE OR A322 ASSN STD 3RD MATERIAL RESPONSE OR A331 ASSN STD 3RD MATERIAL RESPONSE OR A322 ASSN STD 4TH MATERIAL RESPONSE OR A331 ASSN STD 4TH 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.