M5 Countersunk Socket Screws (ISO 10642 / DIN 7991) are specified by thread size, length and head dimensions. The M5 row from the standard is reproduced below, followed by the drill sizes, spanner size and torque values used when installing this size.
M5 Dimensional Row (ISO 10642 / DIN 7991)
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Hex key s (mm) | Countersink angle (deg) | Reference standard |
|---|---|---|---|---|---|---|
| M5 | 0.8 | 11.2 | 3.1 | 3.0 | 90 | ISO 10642 / DIN 7991 |
Spanner & Drive for M5 Countersunk Socket Screws
The hex socket for M5 Countersunk Socket Screws is shown in the spec table — use the matching Allen / hex key (an ISO 2936 hex key set covers the full range). A T-handle Allen key gives the best feel for setting preload by feel; for production work use a torque-controlled driver.
Hole Sizes for M5
| Coarse-thread pitch (ISO 724) | 0.8 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 5.5 mm |
| Tapping drill, coarse thread | 4.2 mm |
Tightening Torque for M5
| Class 8.8 (dry, ~µ 0.125) | ≈ 5.8 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 8.1 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 9.7 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 M5
| Tensile stress area As (ISO 898-1) | 14.2 mm² |
|---|---|
| Proof load, class 8.8 | 8.2 kN |
| Proof load, class 10.9 | 11.8 kN |
| Proof load, class 12.9 | 13.8 kN |
| Min. ultimate tensile, class 8.8 | 11.4 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.
Common Applications for M5 Countersunk Socket Screws
M5 Countersunk Socket Screws are commonly specified for electronics, PCB hardware, optical mounts and small-scale machinery.
Mating Parts for M5
For M5, pair with a M5 hex nut (ISO 4032 / DIN 934) and, where used, a M5 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M5
When the joint preload approaches the proof load of M5 class 8.8, step up to M6 class 8.8 (or move to M5 class 10.9). When the joint is over-specified, M4 often saves weight and cost without losing the safety margin.