| THREAD SERIES DESIGNATOR | UNC |
| PART NAME ASSIGNED BY CONTROLLING AGENCY | NAVY SPECIAL PROJECT |
| THREAD CLASS | 3A |
| HEAD STYLE | HEXAGON |
| FASTENER LENGTH | 1.510 INCHES MINIMUM AND 1.525 INCHES MAXIMUM |
| THREAD QUANTITY PER INCH | 18 |
| INTERNAL DRIVE STYLE | HEXAGON |
| GROOVE DIAMETER | 0.252 INCHES MINIMUM AND 0.262 INCHES MAXIMUM |
| WIDTH ACROSS FLATS | 0.250 INCHES MINIMUM AND 0.253 INCHES MAXIMUM |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-35,TY II FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| MATERIAL | STEEL COMP 630 OVERALL |
| THREAD DIRECTION | RIGHT-HAND |
| NOMINAL THREAD DIAMETER | 0.312 INCHES |
| WIDTH BETWEEN FLATS | 0.490 INCHES MINIMUM AND 0.500 INCHES MAXIMUM |
| MATERIAL DOCUMENT AND CLASSIFICATION | AMS 5643 FED SPEC SINGLE MATERIAL RESPONSE OVERALL |
| THREAD LENGTH | 0.520 INCHES MINIMUM AND 0.530 INCHES MAXIMUM |
| HEAD HEIGHT | 0.307 INCHES MINIMUM AND 0.312 INCHES MAXIMUM |