Metric fine
Tap drill 53 mm for a M56 × 3.0 thread — major Ø 56 mm, pitch 3 mm (8.47 TPI).
Profile
| Designation | M56 × 3.0 |
|---|---|
| Major (outside) diameter | 56 mm · 2.2047" |
| Pitch | 3 mm · 8.47 TPI |
| Pitch diameter | 54.052 mm · 2.128" |
| Minor diameter (external) | 52.319 mm · 2.0598" |
| Minor diameter (internal) | 52.753 mm · 2.0769" |
| Recommended tap drill | 53 mm · ≈77% thread |
| Clearance hole | Close 58 · Normal 62 · Loose 66 mm |
| Hex head (across flats) | 85 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 | 2221.6 mm² | 966.42 kN | 10823.9 N·m |
| Class 10.9 | 2221.6 mm² | 1382.97 kN | 15489.3 N·m |
| Class 12.9 | 2221.6 mm² | 1616.25 kN | 18102 N·m |
For a M56 × 3.0 thread, drill the hole with a 53 mm tap drill (53 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 56 mm and a pitch of 3 mm (8.47 TPI).
To pass a M56 × 3.0 bolt through a part rather than thread it, use a clearance hole: Close 58 · Normal 62 · Loose 66 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.
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