| THREAD SERIES DESIGNATOR | UNF |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| THREAD QUANTITY PER INCH | 28 |
| THREAD CLASS | 3A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.225 INCHES MINIMUM |
| FASTENER LENGTH | 1.781 INCHES NOMINAL |
| MATERIAL | STEEL COMP 4140 OR |
| STEEL COMP 8740 OR |
| STEEL COMP 8630 OR |
| STEEL COMP 8735 OR |
| STEEL COMP 4130 OR |
| STEEL COMP 4037 OVERALL |
| MATERIAL DOCUMENT AND CLASSIFICATION | MIL-S-5626 MIL SPEC 1ST MATERIAL RESPONSE OR |
| MIL-S-6049 MIL SPEC 2ND MATERIAL RESPONSE OR |
| MIL-S-6050 MIL SPEC 3RD MATERIAL RESPONSE OR |
| MIL-S-6098 MIL SPEC 4TH MATERIAL RESPONSE OR |
| MIL-S-6758 MIL SPEC 5TH MATERIAL RESPONSE OR |
| AMS 6300 ASSN STD 6TH MATERIAL RESPONSE OVERALL |
| SURFACE TREATMENT | CADMIUM AND |
| CHROMATE OVERALL |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TY 2 CL 3 FED SPEC ALL TREATMENT RESPONSES OVERALL |
| HEAD STYLE | BUTTON |
| HEAD DIAMETER | 0.500 INCHES NOMINAL |
| HEAD HEIGHT | 0.125 INCHES NOMINAL |
| INTERNAL DRIVE STYLE | SLOT |
| GROOVE DIAMETER | 0.191 INCHES MINIMUM AND |
| 0.201 INCHES MAXIMUM |
| DISTANCE FROM HEAD LARGEST BEARING SURFACE TO SHANK HOLE CENTER | 1.610 INCHES MINIMUM AND |
| 1.642 INCHES MAXIMUM FIRST HOLE |
| SHANK UNTHREADED HOLE DIAMETER | 0.076 INCHES MINIMUM AND |
| 0.086 INCHES MAXIMUM FIRST HOLE |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 88044 |
| DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | AN24-28 |