| THREAD SERIES DESIGNATOR | UNC |
| NOMINAL THREAD DIAMETER | 0.216 INCHES |
| THREAD QUANTITY PER INCH | 24 |
| THREAD CLASS | 2A |
| THREAD LENGTH | 0.644 INCHES MINIMUM AND |
| 0.706 INCHES MAXIMUM |
| FASTENER LENGTH | 0.688 INCHES MINIMUM AND |
| 0.750 INCHES MAXIMUM |
| MATERIAL | STEEL COMP 1070 OR |
| STEEL COMP 1566 PRIMARY WASHER |
| MATERIAL DOCUMENT AND CLASSIFICATION | 66 FED STD ALL MATERIAL RESPONSES PRIMARY WASHER |
| 66 FED STD ALL MATERIAL RESPONSES FASTENER |
| SURFACE TREATMENT | CADMIUM OR |
| ZINC OVERALL |
| 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 |
| HARDNESS RATING | 40.0 ROCKWELL C NOMINAL PRIMARY WASHER |
| HEAD STYLE | ROUND |
| HEAD DIAMETER | 0.382 INCHES MINIMUM AND |
| 0.408 INCHES MAXIMUM |
| HEAD HEIGHT | 0.139 INCHES MINIMUM AND |
| 0.153 INCHES MAXIMUM |
| INTERNAL DRIVE STYLE | SLOT |
| WASHER QUANTITY | 1 |
| PRIMARY WASHER STYLE | FLAT EXTERNAL TEETH |
| PRIMARY WASHER OUTSIDE DIAMETER | 0.395 INCHES MINIMUM AND |
| 0.406 INCHES MAXIMUM |
| PRIMARY WASHER MATERIAL THICKNESS | 0.022 INCHES NOMINAL |
| SPEC/STD CONTROLLING DATA | |
| MANUFACTURERS CODE | 21450 |
| DEFINITIVE GOVERNMENT SPEC/STD REFERENCE | 420982 |