The Nut,self-Locking,extended Washer, cataloged under National Stock Number 5310-01-306-9048, is classified within Federal Supply Class 5310 (Nuts and Washers) of the Hardware and Abrasives group. The manufacturer of record is Sps Technologies, Llc Dba PB Fasteners. Government technical data includes 16 specifications, cited from the U.S. Government catalog. The record lists 6 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 11 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5310-01-306-9048 |
| Primary Part Number | KFN668-4 |
| Item Name | Nut,self-Locking,extended Washer |
| FSC / FSG | 5310 / 53 — Nuts and Washers |
| Manufacturer | Sps Technologies, Llc Dba PB Fasteners |
| Status | ACTIVE |
| Lubrication | DRY FILM LUBRICANT |
| Washer Outside Diameter | 0.425 INCHES MAXIMUM IN |
| Width Across Flats | 0.305 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | QQ-P-35 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| Thread Series | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Material Document and Classification | AMS 5643 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nut Counterbore Depth | 0.107 INCHES MINIMUM AND 0.117 INCHES MAXIMUM WASHER IN |
| Thread Direction | RIGHT-HAND |
| Nominal Thread Size | 0.250 INCHES IN |
| Counterbore Diameter | 0.284 INCHES MINIMUM AND 0.288 INCHES MAXIMUM WASHER IN |
| Locking Feature | PREVAILING TORQUE ALL METAL DESIGN |
| Surface Treatment | PASSIVATE OVERALL |
| Nut Style | HEXAGON |
| Thread Class | 3B |
| Thread Quantity Per Inch | 28 |
| Material | IRON ALLOY 660 OVERALL |
| 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 |
|---|---|
| BH00620M4 | Bristol Industries, Llc (USA) |
| KFN668-4 | Howmet Global Fastening Systems Inc (USA) |
| 03A136-4L | Northrop Grumman Systems Corp Dba Northrop Grumman Computing Systems (USA) |
| KFN668-4 | Huck International, Inc (USA) |
| KFN668-4 PRIMARY | Sps Technologies, Llc Dba PB Fasteners (USA) |
| 03A136-4L | Northrop Grumman Systems Corporation Dba Northrop Grumman Is Div Northrop Grumman Aeronautics Systems (USA) |
| Reference | Meaning |
|---|---|
| KFN517DL4 | 5/9 Secondary reference Howmet Global Fastening Systems Inc |
| KFN511DL4 | C/1 Advisory reference — outside the item-of-supply concept Howmet Global Fastening Systems Inc |
| LE114-0031-0004 | 7/2 Vendor item drawing reference The Boeing Company Div Legacy Am&m |
| KFN668-4 | 5/9 Secondary reference U.S. Government activity |
| KFN511DL4 | 5/9 Secondary reference U.S. Government activity |
| KFN511DL4 | 5/9 Secondary reference Sps Technologies, Llc Dba PB Fasteners |
| KFN511DL-4 | 5/9 Secondary reference U.S. Government activity |
| KFN511DL4 | 5/9 Secondary reference Panametrics Llc |
| KFN668-4 | 5/9 Secondary reference Deutsch Fastener Corp |
| BH136M-4L | 5/9 Secondary reference Bristol Industries, Llc |
| KFN511DL4 | 5/9 Secondary reference Ge Kaye Instruments Inc |
NSN 5310-01-306-9048 is a Nut,self-Locking,extended Washer, manufactured by Sps Technologies, Llc Dba PB Fasteners, classified under FSC 5310, Nuts and Washers. Status: active.
NSN 5310-01-306-9048 has 6 manufacturer part numbers on file: BH00620M4 (Bristol Industries, Llc), KFN668-4 (Howmet Global Fastening Systems Inc), 03A136-4L (Northrop Grumman Systems Corp Dba Northrop Grumman Computing Systems), KFN668-4 (Huck International, Inc), KFN668-4 (Sps Technologies, Llc Dba PB Fasteners) and 1 more.
Key specifications for KFN668-4: Lubrication: DRY FILM LUBRICANT; Overall Height: 0.340 INCHES MAXIMUM IN; Washer Outside Diameter: 0.425 INCHES MAXIMUM IN; Width Across Flats: 0.305 INCHES MINIMUM AND 0.313 INCHES MAXIMUM IN. 16 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.