Metric
(ISO 10642) A conical head that sits flush with the surface of the part.
| Thread Designation | Head Diameter (mm) | Head Height (mm) | Clearance Hole (mm) | Thread Pitch (mm) |
|---|---|---|---|---|
| M2 | 4.4 | 1.2 | 2.4 | 0.40 |
| M2.5 | 5.5 | 1.5 | 2.9 | 0.45 |
| M3 | 6.0 | 1.7 | 3.4 | 0.50 |
| M4 | 8.0 | 2.3 | 4.5 | 0.70 |
| M5 | 10.0 | 2.8 | 5.5 | 0.80 |
| M6 | 12.0 | 3.3 | 6.6 | 1.00 |
| M8 | 16.0 | 4.4 | 9.0 | 1.25 |
| M10 | 20.0 | 5.5 | 11.0 | 1.50 |
| M12 | 24.0 | 6.5 | 13.5 | 1.75 |
| M14 | 27.0 | 7.0 | 15.5 | 2.00 |
| M16 | 30.0 | 7.5 | 17.5 | 2.00 |
| M20 | 36.0 | 8.5 | 22.0 | 2.50 |
| M24 | 39.0 | 14.0 | 26.0 | 3.00 |
Imperial
Countersunk (Flat Head) screws follow the ASME B18.3 standard.
Note: These feature an 82-degree countersink angle (standard for Imperial), unlike the 90-degree angle often found in Metric ISO standards.
| Thread Designation | Head Diameter (in) | Head Height (in) | Clearance Hole (in) | Threads Per Inch (TPI) |
|---|---|---|---|---|
| #4-40 | 0.255" | 0.083" | 0.128" | 40 |
| #6-32 | 0.307" | 0.097" | 0.149" | 32 |
| #8-32 | 0.359" | 0.112" | 0.177" | 32 |
| #10-24 | 0.411" | 0.127" | 0.204" | 24 |
| 1/4"-20 | 0.531" | 0.161" | 17/64" | 20 |
| 5/16"-18 | 0.656" | 0.198" | 21/64" | 18 |
| 3/8"-16 | 0.781" | 0.234" | 25/64" | 16 |
| 1/2"-13 | 0.938" | 0.251" | 17/32" | 13 |
| 5/8"-11 | 1.188" | 0.324" | 21/32" | 11 |
| 3/4"-10 | 1.438" | 0.396" | 25/32" | 10 |
| 7/8"-9 | 1.688" | 0.468" | 29/32" | 9 |
| 1"-8 | 1.938" | 0.540" | 1-1/16" | 8 |