Metric fine
Tap drill 10.75 mm for a M12 × 1.25 thread — major Ø 12 mm, pitch 1.25 mm (20.32 TPI).
Profile
| Designation | M12 × 1.25 |
|---|---|
| Major (outside) diameter | 12 mm · 0.4724" |
| Pitch | 1.25 mm · 20.32 TPI |
| Pitch diameter | 11.188 mm · 0.4405" |
| Minor diameter (external) | 10.466 mm · 0.4121" |
| Minor diameter (internal) | 10.647 mm · 0.4192" |
| Recommended tap drill | 10.75 mm · ≈77% thread |
| Clearance hole | Close 13 · Normal 13.5 · Loose 14.5 mm |
| Hex head (across flats) | 18 mm |
| Socket key (across flats) | 10 mm |
ISO 273 clearance holes (fine / medium / coarse).
Target preload is 75% of proof load; torque is estimated from T = K · F · d.
| Grade / class | Stress area | Preload | Torque |
|---|---|---|---|
| Class 8.8 | 92.1 mm² | 40.05 kN | 96.1 N·m |
| Class 10.9 | 92.1 mm² | 57.31 kN | 137.6 N·m |
| Class 12.9 | 92.1 mm² | 66.98 kN | 160.8 N·m |
For a M12 × 1.25 thread, drill the hole with a 10.75 mm tap drill (10.75 mm — the standard D − P rule) before tapping. That produces roughly 77% thread engagement, the usual target for a strong, tappable hole. The mating bolt has a major diameter of 12 mm and a pitch of 1.25 mm (20.32 TPI).
To pass a M12 × 1.25 bolt through a part rather than thread it, use a clearance hole: Close 13 · Normal 13.5 · Loose 14.5 mm.
All values are generated from the standard thread formulas (ISO 68-1 / ASME B1.1) and published standard tables — not hand-entered. See the full reference.
Same diameter
Nearby sizes