M14 × 1.5 Thread
The chart recommendation gives approximately 77% thread engagement — the conventional target for average materials. It is not the only valid choice; see the options below.
Specification
| Designation | M14 × 1.5 |
|---|---|
| Thread family | ISO metric fine |
| Nominal size | M14 |
| Basic major diameter | 0.5512″ / 14 mm |
| Pitch | 1.5 mm |
| Recommended tap drill | 12.5 mm (0.4921″ / 12.5 mm) |
Tap drill options by thread engagement
Any of these standard drills produces a usable engagement for M14 × 1.5; smaller drills give stronger threads but higher tapping torque. Percentages use the conventional approximation (60° thread form).
| Drill | Decimal in | mm | Approx. engagement |
|---|---|---|---|
| 12.4 mm | 0.4882 | 12.4 | 82.1% |
| 12.5 mm — chart recommendation | 0.4921 | 12.5 | 77% |
| 12.6 mm | 0.4961 | 12.6 | 71.8% |
| 1/2″ | 0.5000 | 12.7 | 66.7% |
| 12.7 mm | 0.5000 | 12.7 | 66.7% |
| 12.8 mm | 0.5039 | 12.8 | 61.6% |
Nearest drills to the tap drill in other systems
| Drill | Size | vs 12.5 mm | Resulting engagement |
|---|---|---|---|
| 31/64″ | 0.4844″ / 12.303 mm | −0.197 mm | 87.1% |
Clearance holes
For a bolt or screw of this size to pass through freely. ISO 273 series (fine/medium/coarse), shown as close, normal, and loose.
| Fit | Drill / Ø | Decimal in | mm |
|---|---|---|---|
| close | 15 mm | 0.5906 | 15 |
| normal | 15.5 mm | 0.6102 | 15.5 |
| loose | 16.5 mm | 0.6496 | 16.5 |
Hex bolt & nut dimensions
For a standard hex bolt (ISO 4014/4017) and style-1 nut (ISO 4032) in this size.
| Wrench / socket size (bolt head) | 21 mm — legacy DIN: 22 mm |
|---|---|
| Head height | 8.8 mm |
| Nut thickness | 12.8 mm |
| Compatible nut | M14 × 1.5 hex nut |
Basic (nominal) dimensions. See the wrench & socket size charts for all sizes and the metric ↔ SAE socket comparison.
Related threads
- M14 × 2 — same nominal size, 2 mm pitch (ISO metric coarse) · compare
- M12 × 1.5 — next size down in metric-fine
- M16 × 1.5 — next size up in metric-fine