METRICcoarse60° flank
M33 × 3.5 Thread Dimensions
M33 x 3.5 is a coarse pitch METRIC thread. Pitch is 3.5 mm, equivalent to 7.26 threads per inch. The recommended tap drill leaves roughly 75% thread engagement.
Nominal Ø33 mm
Pitch3.5 mm
Threads per inch7.26
Pitch Ø30.73 mm
Tap drill29.5 mm
Thread profile
millimetres unless stated- Designation
- M33 x 3.5
- Thread system
- METRIC
- Series
- coarse
- Flank angle
- 60°
- Major diameter
- 33 mm / 1.3"
- Pitch
- 3.5 mm
- Threads per inch
- 7.26
- Pitch diameter
- 30.73 mm
- Minor diameter (external)
- 28.71 mm
- Minor diameter (internal)
- 29.21 mm
- Thread depth
- 2.15 mm
- Recommended tap drill
- Ø 29.5 mm / 1.16"
How these values are derived
Basic ISO thread geometry uses the fundamental triangle height H = 0.866025 × P. External minor diameter d₃ = d − 1.226869 × P, internal minor diameter D₁ = d − 1.082532 × P. Tap drill is given as nominal diameter minus pitch, which approximates a 75% thread engagement — adjust for tough materials or deep holes.