Inch series · controlled reference
Flat Head Screw Dimensions — CRES UNF-2A
Complete nominal-size table from U.S. DoD detail sheet MS51960D for 300-series corrosion-resistant, 82° cross-recessed flat head machine screws. The sheet covers 0.060 through 0.750 in, UNF-2A.
Source: U.S. DoD MS51960D, Table I; its current DoD validation record is dated 21 April 2026.
| Nominal size | TPI · UNF-2A | A — head Ø max / min sharp | H ref / H1 undercut max–min | Driver size |
|---|---|---|---|---|
| 0.060 in | 80 | 0.119 / 0.105 | 0.035 ref / 0.025–0.018 | #0 |
| 0.086 in | 64 | 0.172 / 0.156 | 0.051 ref / 0.036–0.028 | #1 |
| 0.112 in | 48 | 0.225 / 0.207 | 0.067 ref / 0.047–0.038 | #1 |
| 0.138 in | 40 | 0.279 / 0.257 | 0.083 ref / 0.059–0.048 | #2 |
| 0.164 in | 36 | 0.332 / 0.308 | 0.100 ref / 0.070–0.058 | #2 |
| 0.190 in | 32 | 0.385 / 0.359 | 0.116 ref / 0.081–0.068 | #2 |
| 0.250 in | 28 | 0.507 / 0.477 | 0.153 ref / 0.107–0.092 | #3 |
| 0.3125 in | 24 | 0.635 / 0.600 | 0.191 ref / 0.134–0.116 | #4 |
| 0.375 in | 24 | 0.762 / 0.722 | 0.230 ref / 0.161–0.140 | #4 |
| 0.4375 in | 20 | 0.812 / 0.767 | 0.223 ref / 0.156–0.133 | #4 |
| 0.500 in | 20 | 0.875 / 0.831 | 0.223 ref / 0.156–0.130 | #4 |
| 0.5625 in | 18 | 1.000 / 0.950 | 0.260 ref / 0.182–0.153 | #4 |
| 0.625 in | 18 | 1.125 / 1.069 | 0.298 ref / 0.208–0.176 | #5 |
| 0.750 in | 16 | 1.375 / 1.306 | 0.372 ref / 0.260–0.223 | #5 |