The M3 size of Vented Vacuum Screws is dimensioned by ISO 4762. The tables below give the dimensional row from the standard, the drill and spanner sizes that go with it, and the assembly torque per property class. The technical drawing on this page redraws to the exact values selected.
M3 Dimensional Row (ISO 4762)
| Thread size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Hex socket s (mm) | Vent hole diameter (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M3 | 0.5 | 5.5 | 3.0 | 2.5 | 0.8 | 6~30 | ISO 4762 vented |
Spanner & Drive for M3 Vented Vacuum Screws
Drive geometry for M3 Vented Vacuum Screws is given by the row above; match the tool to the listed values.
Hole Sizes for M3
| Coarse-thread pitch (ISO 724) | 0.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 3.4 mm |
| Tapping drill, coarse thread | 2.5 mm |
Tightening Torque for M3
| Class 8.8 (dry, ~µ 0.125) | ≈ 1.3 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 1.8 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 2.1 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 M3
| Tensile stress area As (ISO 898-1) | 5.03 mm² |
|---|---|
| Proof load, class 8.8 | 2.9 kN |
| Proof load, class 10.9 | 4.2 kN |
| Proof load, class 12.9 | 4.9 kN |
| Min. ultimate tensile, class 8.8 | 4 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.
M3 Vented Vacuum Screws Weight
A steel M3 vented vacuum screws at the listed 630 mm length weighs approximately 117 g each — about 117 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 M3 Vented Vacuum Screws
M3 Vented Vacuum Screws are commonly specified for electronics, PCB hardware, optical mounts and small-scale machinery.
Installation Tips for M3 Vented Vacuum Screws
- At M3 the joint is sensitive to over-torque — use a torque-limiting driver and check the head doesn't bury into a softer counterpart.
When to Step Up or Down from M3
When the joint preload approaches the proof load of M3 class 8.8, step up to M4 class 8.8 (or move to M3 class 10.9). When the joint is over-specified, M2 often saves weight and cost without losing the safety margin.
