DIN 912 M33
Socket head cap screw,hex drive
- Thread M33 × 3.5
- Hex key 24 mm
- Tap drill Ø 29.5 mm
Dimensions and tolerances (mm)
| min | nom. | max | |
|---|---|---|---|
| d | |||
| dk | |||
| k | |||
| s | |||
| t |
Values per DIN 912:1983.
In bold: the value shown in the table on the standard page.
Design and assembly (mm)
- Tap drillDIN 336, coarse thread
- Ø 29.5
- Clearance holeISO 273, dh by fit
- close Ø 34.0normal Ø 36.0loose Ø 38.0
Mechanical properties
Preload and torque for: medium clearance hole (ISO 273), tightening to ν = 90 % of yield, coarse thread, µG = µK = 0.14.
| Property class | Loads, ISO 898-1 | Tightening, VDI 2230 | Calculator | ||
|---|---|---|---|---|---|
| ProofkN | BreakkN | PreloadkN | TorqueN·m | ||
| Steel 8.8Steel 8.8 Tensile strength Rm ≥ 830 MPa, yield Rp0.2 ≥ 660 MPa (80 % of Rm). The everyday property class for machine parts. | 416.1 | 575.6 | 363.7 | 2206.1 | Calculate torque |
| Steel 10.9Steel 10.9 Tensile strength Rm ≥ 1040 MPa, yield Rp0.2 ≥ 940 MPa (90 % of Rm). High strength, for heavily loaded joints. | 575.6 | 721.3 | 518.0 | 3142.0 | Calculate torque |
| Steel 12.9Steel 12.9 Tensile strength Rm ≥ 1220 MPa, yield Rp0.2 ≥ 1100 MPa (90 % of Rm). The strongest property class in common use. Sensitive to hydrogen: avoid electroplated coatings. The property class this standard is usually made in.usual | 672.7 | 846.1 | 606.2 | 3676.8 | Calculate torque |
| Stainless A2-70Stainless A2-70 Austenitic stainless A2 (like AISI 304): general corrosion resistance. | Property class A2-70 does not cover M33. | ||||
| Stainless A4-80Stainless A4-80 Austenitic stainless A4 (like AISI 316, with molybdenum): for sea water and chemicals. | Property class A4-80 does not cover M33. | ||||
* Stainless: load at yield (Rp0.2 × As); ISO 3506-1 gives no proof load.
Stainless steel: the real friction is higher and scatters widely, so the torque shown is only a starting point; type your own µ in the box.
- Stress area As
- 693.6 mm²
- Shank area A
- 855.3 mm²
Standard threads (mm)
| P | d₂ | d₃ | |
|---|---|---|---|
| M33Coarse (most common) | 3.50 | 30.727 | 28.706 |
| M33 × 2Fine | 2.00 | 31.701 | 30.546 |
Profile per ISO 68-1 · tolerance class 6g
Thread length (mm)
Screws up to about 78 mm are fully threaded.Longer ones are threaded for b = 78 mm.
Verified data
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References
- DIN 912:1983 Hexagon socket head cap screws
- ISO 4762:2004 Hexagon socket head cap screws
- ISO 262:1998 ISO general purpose metric screw threads — Selected sizes for screws, bolts and nuts
- ISO 68-1:1998 ISO general purpose screw threads — Basic profile — Part 1: Metric screw threads
- ISO 898-1:2013 Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws and studs
- ISO 3506-1:2020 Fasteners — Mechanical properties of corrosion-resistant stainless steel fasteners — Part 1: Bolts, screws and studs
- VDI 2230 Part 1:2015 Systematic calculation of highly stressed bolted joints — Joints with one cylindrical bolt
- DIN 336:2003 Diameters of drills for minor diameters of tapped threads
- ISO 273:1979 Fasteners — Clearance holes for bolts and screws