M12 thread: tap drill, clearance hole and counterbore sizes
The hole sizes and depths for an M12 coarse thread, and how to put it on a drawing.
| Property | Value |
|---|---|
| Nominal diameter | 12 mm |
| Pitch (coarse) | 1.75 mm |
| Tap drill | Ø10.2 mm |
| Clearance hole, fine | Ø13 mm |
| Clearance hole, medium | Ø13.5 mm |
| Clearance hole, coarse | Ø14.5 mm |
| Socket head cap screw head Ø (ISO 4762) | 18 mm |
| Counterbore Ø (DIN 974-1) | 20 mm |
| Counterbore depth (head flush) | about 12.5 mm |
Thread depth
| Material | Full thread engagement |
|---|---|
| Steel, stainless steel | 12–18 mm |
| Aluminium, brass | 18–24 mm |
| Plastics | 24–30 mm or an insert |
Drill the tap hole at least 5.3–7 mm (3–4 pitches) deeper than the full thread, plus the drill point. More on this in how deep a tapped thread should be.
How to call it out on a drawing
Tapped blind hole: M12x1.75-6H, thread 18 deep, tap drill Ø10.2 25 deep.
Clearance hole with counterbore: Ø13.5 through, counterbore Ø20 × 12.5 deep.
M10 | M14 | All thread sizes
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