The Washer,flat, cataloged under National Stock Number 5310-01-656-2100, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Mcmaster-Carr Supply Co. Government technical data includes 8 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through both NSN and commercial part number lookups. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-656-2100 |
| Primary Part Number | 91090A127 |
| Item Name | Washer,flat |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Mcmaster-Carr Supply Co |
| Status | ACTIVE |
| Overall Diameter | 2.000 INCHES NOMINAL IN |
| Cross-Sectional Shape Style | RECTANGULAR |
| Surface Treatment | ZINC OVERALL |
| Peripheral Shape Style | ROUND |
| Material | STEEL OVERALL |
| Center Hole Shape Style | ROUND |
| Hole Diameter | 0.344 INCHES NOMINAL IN |
| Thickness | 0.040 INCHES MINIMUM AND 0.060 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 |
|---|---|
| 91090A127 PRIMARY | Mcmaster-Carr Supply Co (USA) |
| Reference | Meaning |
|---|---|
| 19E2401086-2 | 7/2 Vendor item drawing reference Devcom Chemical Biological Center Dba Chemical Biological Center Div U.s. Dept of Army |
| 19E2401086 | D/9 Drawing number reference only Devcom Chemical Biological Center Dba Chemical Biological Center Div U.s. Dept of Army |
NSN 5310-01-656-2100 is a Washer,flat, manufactured by Mcmaster-Carr Supply Co, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-656-2100 has 1 manufacturer part number on file: 91090A127 (Mcmaster-Carr Supply Co).
Key specifications for 91090A127: Overall Diameter: 2.000 INCHES NOMINAL IN; Cross-Sectional Shape Style: RECTANGULAR; Special Features: 5/16 SCREW SIZE; Surface Treatment: ZINC OVERALL. 8 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.