| FASTENER LENGTH | 0.438 INCHES NOMINAL |
| HARDNESS RATING | 45.0 ROCKWELL C MINIMUM AND 53.0 ROCKWELL C MAXIMUM PRIMARY WASHER |
| HEAD DIAMETER | 0.389 INCHES MINIMUM AND 0.414 INCHES MAXIMUM |
| HEAD HEIGHT | 0.155 INCHES MINIMUM AND 0.170 INCHES MAXIMUM |
| HEAD STYLE | FILLISTER |
| INTERNAL DRIVE STYLE | CROSS RECESS TYPE 1 |
| NOMINAL THREAD DIAMETER | 0.250 INCHES |
| PRIMARY WASHER MATERIAL THICKNESS | 0.063 INCHES MINIMUM |
| PRIMARY WASHER OUTSIDE DIAMETER | 0.384 INCHES MINIMUM AND 0.400 INCHES MAXIMUM |
| PRIMARY WASHER STYLE | SPLIT HELICAL RING |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TY 1,CL 3 FED SPEC 1ST TREATMENT RESPONSE OR QQ-Z-325,TY 1,CL 3 FED SPEC 2ND TREATMENT RESPONSE OVERALL |
| SURFACE TREATMENT | CADMIUM OR ZINC OVERALL |
| THREAD CLASS | 2A |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD LENGTH | 0.312 INCHES MAXIMUM |
| THREAD SERIES DESIGNATOR | UNIFIED NATIONAL COARSE (UNC) |
| THREAD QUANTITY PER INCH | 20 |
| WASHER QUANTITY | 1 |