Metric fine
Tap drill 48 mm for a M52 × 4.0 thread — major Ø 52 mm, pitch 4 mm (6.35 TPI).
Profile
| Designation | M52 × 4.0 |
|---|---|
| Major (outside) diameter | 52 mm · 2.0472" |
| Pitch | 4 mm · 6.35 TPI |
| Pitch diameter | 49.402 mm · 1.945" |
| Minor diameter (external) | 47.093 mm · 1.854" |
| Minor diameter (internal) | 47.67 mm · 1.8768" |
| Recommended tap drill | 48 mm · ≈77% thread |
| Clearance hole | Close 54 · Normal 56 · Loose 62 mm |
| Hex head (across flats) | 80 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 | 1828.2 mm² | 795.29 kN | 8271 N·m |
| Class 10.9 | 1828.2 mm² | 1138.08 kN | 11836.1 N·m |
| Class 12.9 | 1828.2 mm² | 1330.05 kN | 13832.5 N·m |
For a M52 × 4.0 thread, drill the hole with a 48 mm tap drill (48 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 52 mm and a pitch of 4 mm (6.35 TPI).
To pass a M52 × 4.0 bolt through a part rather than thread it, use a clearance hole: Close 54 · Normal 56 · Loose 62 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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