Drill Tap Size / Thread Helper
Lookup common metric, UNC/UNF, and fractional tap drill recommendations.
Thread and Tap Lookup
| System | Size | Pitch/TPI | Tap Drill | Notes |
|---|---|---|---|---|
| Metric | M6 | 1.0 | 5.0 mm | - |
| Metric | M8 | 1.25 | 6.8 mm | - |
| Metric | M10 | 1.5 | 8.5 mm | - |
| Metric | M12 | 1.75 | 10.2 mm | - |
| Metric | M14 | 2.0 | 12.0 mm | - |
| UNC | 1/4-20 | - | #7 (0.201 in) | - |
| UNC | 5/16-18 | - | F (0.257 in) | - |
| UNC | 3/8-16 | - | 5/16 (0.3125 in) | - |
| UNC | 1/2-13 | - | 27/64 (0.4219 in) | - |
| UNF | 1/4-28 | - | #3 (0.213 in) | - |
| UNF | 5/16-24 | - | I (0.272 in) | - |
| UNF | 3/8-24 | - | Q (0.332 in) | - |
| UNF | 1/2-20 | - | 29/64 (0.4531 in) | - |
| Fractional | 1/8 NPT | - | 11/32 (0.344 in) | Taper pipe thread |
| Fractional | 1/4 NPT | - | 7/16 (0.438 in) | Taper pipe thread |
Example Values
No examples provided for this tool yet.
Formula and Notes
Reference lookup from stored thread/tap drill table
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Diesel Toolkit provides estimated calculations only and does not replace OEM service information, engineering specs, or manufacturer procedures.