To tap an M8 thread (pitch 1.25 mm), drill a 6.8 mm hole for standard 6H tolerance. Use 7.0 mm for a looser 7H fit. M8 taps are common in engine mounts, pump flanges and general machinery.
| Tolerance class | Drill diameter | Pitch | Thread depth |
|---|---|---|---|
| 6H (standard) | 6.8 mm | 1.25 mm | 10–14 mm |
| 7H (loose) | 7.0 mm | 1.25 mm | 10–14 mm |
| 4H (tight) | 6.6 mm | 1.25 mm | 10–14 mm |
Fine pitch M8×1.0 variant available in Handbook Locksmith app.
FAQ
6.8 mm for standard M8 thread (6H, pitch 1.25 mm).
Full M8 thread data in the app
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← Metric threads | See also: M3 · M4 · M5 · M6 · M10 · M12 · M16 · M20 · Spindle speed calculator