Metric coarse · cutting tap · nominal dimensions
M1.4 × 0.3
tap drill size.
For M1.4 × 0.3, the reference drill is 1.1 mm: 0.0433 in (1.100 mm).
The reference value is kept separate from the 70% and 75% calculated targets. Actual fit still depends on thread class, tool, material, runout, and the hole you really make.
Detail A · basic 60° profile
What the percentage describes.
“Theoretical full thread %” is radial thread height from nominal geometry. It is not axial engagement length and not a fit-class acceptance measurement.
Real drill alternatives
Neighboring sizes.
These are diameter neighbors, not silent recommendations. A positive delta makes a larger hole and a lower nominal theoretical percentage; a negative delta does the opposite.
| Bit | System | Diameter | Delta | Calculated full thread |
|---|---|---|---|---|
| #57 | number | 0.0430 in / 1.092 mm | -0.0003 in | 79.0% |
| #58 | number | 0.0420 in / 1.067 mm | -0.0013 in | 85.5% |
| #59 | number | 0.0410 in / 1.041 mm | -0.0023 in | 92.0% |
| #56 | number | 0.0465 in / 1.181 mm | +0.0032 in | 56.2% |
| #60 | number | 0.0400 in / 1.016 mm | -0.0033 in | 98.5% |
| 3/64 | fractional | 3/64 in / 1.191 mm | +0.0036 in | 53.7% |
Why 3D is useful here
A thread is a helix, not a row of triangles.
Load a draggable cutaway to see the continuous internal thread. Exact diameter and profile comparisons remain in the 2D drawing above.
Evidence and limits
Why this row says provisional.
Tap-drill row: A familiar chart or D-minus-pitch value that was not closed against a single row in the selected OSG/Guhring public tables. Kept visible for audit, never labeled normative or manufacturer-published.
Open Drill Bit Size Chart source
60° geometry: Public primary reference for Unified and metric 60-degree thread geometry. The percentage-thread equation is a theoretical basic-profile calculation, not a fit or torque guarantee.
Open National Institute of Standards and Technology geometry source
The repository also records 11 source records and a dataset version on every page.