Metric coarse · cutting tap · nominal dimensions
M4 × 0.7
tap drill size.
For M4 × 0.7, the reference drill is 3.3 mm: 0.1299 in (3.300 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 |
|---|---|---|---|---|
| #30 | number | 0.1285 in / 3.264 mm | -0.0014 in | 81.0% |
| 3.2 mm | metric | 0.1260 in / 3.2 mm | -0.0039 in | 88.0% |
| 3.4 mm | metric | 0.1339 in / 3.4 mm | +0.0039 in | 66.0% |
| 1/8 | fractional | 1/8 in / 3.175 mm | -0.0049 in | 90.7% |
| #29 | number | 0.1360 in / 3.454 mm | +0.0061 in | 60.0% |
| 3.1 mm | metric | 0.1220 in / 3.1 mm | -0.0079 in | 99.0% |
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 cross-checked.
Tap-drill row: Rows tagged with this source were matched to a named 65% or 75% cutting-tap column. The discrete drill can calculate to a slightly different percentage from nominal dimensions.
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.