M1.6 × 0.35 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 | M1.6 × 0.35 |
|---|---|
| Thread family | ISO metric coarse |
| Nominal size | M1.6 |
| Basic major diameter | 0.0630″ / 1.6 mm |
| Pitch | 0.35 mm |
| Recommended tap drill | 1.25 mm (0.0492″ / 1.25 mm) |
Tap drill options by thread engagement
Any of these standard drills produces a usable engagement for M1.6 × 0.35; smaller drills give stronger threads but higher tapping torque. Percentages use the conventional approximation (60° thread form).
| Drill | Decimal in | mm | Approx. engagement |
|---|---|---|---|
| 1.25 mm — chart recommendation | 0.0492 | 1.25 | 77% |
| 1.3 mm | 0.0512 | 1.3 | 66% |
| #55 | 0.0520 | 1.321 | 61.4% |
Nearest drills to the tap drill in other systems
| Drill | Size | vs 1.25 mm | Resulting engagement |
|---|---|---|---|
| 3/64″ | 0.0469″ / 1.191 mm | −0.059 mm | 90% |
| #56 | 0.0465″ / 1.181 mm | −0.069 mm | 92.1% |
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.
Related threads
- M2 × 0.4 — next size up in metric-coarse