M12 is one of the standard coarse-thread sizes for sealing screws with bonded washer under DIN 933. The sections below reproduce the dimensional row, list the matching tools and hole sizes, and summarize where this size is normally specified.
M12 Dimensional Row (DIN 933)
| Thread size | Pitch (mm) | Across flats s (mm) | Head height k (mm) | Seal outer diameter (mm) | Seal thickness (mm) | Seal material | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|
| M12 | 1.75 | 19 | 7.5 | 19 | 2.0 | NBR | 20~80 | DIN 933 + BS 4518 |
Spanner & Drive for M12 Sealing Screws with Bonded Washer
Drive geometry for M12 Sealing Screws with Bonded Washer is given by the row above; match the tool to the listed values.
Hole Sizes for M12
| Coarse-thread pitch (ISO 724) | 1.75 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 13.5 mm |
| Tapping drill, coarse thread | 10.2 mm |
Tightening Torque for M12
| Class 8.8 (dry, ~µ 0.125) | ≈ 85 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 120 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 145 Nm |
Indicative dry-joint values. Lubrication can lower the required torque by 15–25%. Always confirm against the joint design, especially when going up a strength class.
Proof Load & Strength for M12
| Tensile stress area As (ISO 898-1) | 84.3 mm² |
|---|---|
| Proof load, class 8.8 | 49 kN |
| Proof load, class 10.9 | 70 kN |
| Proof load, class 12.9 | 82 kN |
| Min. ultimate tensile, class 8.8 | 67 kN |
Proof load = stress area × proof stress per ISO 898-1. Design joints so the working preload stays below the proof load of the selected class.
M12 Sealing Screws with Bonded Washer Weight
A steel M12 sealing screws with bonded washer at the listed 2,080 mm length weighs approximately 1,865 g each — about 1,865 kg per 1,000 pieces. Stainless A2/A4 weighs roughly the same (density 7.9–8.0 g/cm³). Actual weight varies slightly with head form, thread and finish; use this figure for freight estimation only.
Common Applications for M12 Sealing Screws with Bonded Washer
M12 Sealing Screws with Bonded Washer are commonly specified for heavier machine assembly and equipment mounting.
Mating Parts for M12
For M12, pair with a M12 hex nut (ISO 4032 / DIN 934) and, where used, a M12 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M12
When the joint preload approaches the proof load of M12 class 8.8, step up to M16 class 8.8 (or move to M12 class 10.9). When the joint is over-specified, M10 often saves weight and cost without losing the safety margin.
