| THREAD SERIES DESIGNATOR | UNF |
| NOMINAL THREAD DIAMETER | 0.138 INCHES |
| THREAD QUANTITY PER INCH | 40 |
| THREAD CLASS | 2A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.218 INCHES MINIMUM |
| FASTENER LENGTH | 0.250 INCHES NOMINAL |
| MATERIAL | COPPER ALLOY 510 OR |
| COPPER ALLOY 524 OR |
| COPPER ALLOY 544 PRIMARY WASHER |
| COPPER ALLOY 360 FASTENER |
| MATERIAL DOCUMENT AND CLASSIFICATION | QQ-B-750 FED SPEC ALL MATERIAL RESPONSES PRIMARY WASHER |
| QQ-B-626,1/2 HARD FED SPEC SINGLE MATERIAL RESPONSE FASTENER |
| HARDNESS RATING | 60.0 ROCKWELL B MINIMUM AND |
| 90.0 ROCKWELL B MAXIMUM FASTENER |
| HEAD STYLE | FILLISTER |
| HEAD DIAMETER | 0.208 INCHES MINIMUM AND |
| 0.226 INCHES MAXIMUM |
| HEAD HEIGHT | 0.086 INCHES MINIMUM AND |
| 0.096 INCHES MAXIMUM |
| INTERNAL DRIVE STYLE | SLOT |
| WASHER QUANTITY | 1 |
| PRIMARY WASHER STYLE | FLAT INTERNAL TEETH |
| PRIMARY WASHER OUTSIDE DIAMETER | 0.278 INCHES MINIMUM AND |
| 0.288 INCHES MAXIMUM |
| PRIMARY WASHER MATERIAL THICKNESS | 0.021 INCHES NOMINAL |