M24 thread: tap drill, clearance hole and counterbore sizes
The hole sizes and depths for an M24 coarse thread, and how to put it on a drawing.
| Property | Value |
|---|---|
| Nominal diameter | 24 mm |
| Pitch (coarse) | 3 mm |
| Tap drill | Ø21 mm |
| Clearance hole, fine | Ø25 mm |
| Clearance hole, medium | Ø26 mm |
| Clearance hole, coarse | Ø28 mm |
| Socket head cap screw head Ø (ISO 4762) | 36 mm |
| Counterbore Ø (DIN 974-1) | 40 mm |
| Counterbore depth (head flush) | about 24.5 mm |
Thread depth
| Material | Full thread engagement |
|---|---|
| Steel, stainless steel | 24–36 mm |
| Aluminium, brass | 36–48 mm |
| Plastics | 48–60 mm or an insert |
Drill the tap hole at least 9–12 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: M24x3-6H, thread 36 deep, tap drill Ø21 48 deep.
Clearance hole with counterbore: Ø26 through, counterbore Ø40 × 24.5 deep.
M20 | M30 | All thread sizes
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