| HARDNESS RATING | 49.0 ROCKWELL C MAXIMUM |
| LOCKING FEATURE | PREVAILING TORQUE ALL METAL DESIGN |
| NUT STYLE | HEXAGON |
| OVERALL HEIGHT | 0.253 INCHES MINIMUM AND 0.266 INCHES MAXIMUM |
| MATERIAL | STEEL CORROSION RESISTING OVERALL |
| NOMINAL THREAD SIZE | 0.312 INCHES |
| WASHER THICKNESS | 0.023 INCHES MINIMUM |
| WASHER OUTSIDE DIAMETER | 0.520 INCHES NOMINAL |
| WIDTH ACROSS FLATS | 0.367 INCHES MINIMUM AND 0.378 INCHES MAXIMUM |
| SPECIFICATION/STANDARD DATA | 80205-NAS1291 PROFESSIONAL/INDUSTRIAL ASSOCIATION STANDARD |
| SURFACE TREATMENT DOCUMENT AND CLASSIFICATION | QQ-P-416,TYPE 2,CLASS 1 OR 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL |
| SURFACE TREATMENT | CADMIUM OVERALL |
| THREAD CLASS | 3B |
| THREAD DIRECTION | RIGHT-HAND |
| THREAD QUANTITY PER INCH | 24 |
| THREAD SERIES | UNIFIED NATIONAL JOINT FINE (UNJF) |