On the bench specifying M4 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)? This page gives the controlling dimensions for the M4 size of Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037) (to GB/T 825 / DIN 580).
M4 Dimensional Row (GB/T 825 / DIN 580)
| Size | Pitch (mm) | Length L (mm) | Head diameter dk (mm) | Head height k (mm) | Hex socket s (mm) | Reference standard |
|---|---|---|---|---|---|---|
| M4 | 0.7 | 25 | 7.0 | 4 | 3.0 | ISO 4762 / GB/T 70.1 |
Spanner & Drive for M4 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)
The hex socket for M4 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037) 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 M4
| Coarse-thread pitch (ISO 724) | 0.7 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 4.5 mm |
| Tapping drill, coarse thread | 3.3 mm |
Tightening Torque for M4
| Class 8.8 (dry, ~µ 0.125) | ≈ 2.9 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 4.1 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 4.9 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.
Common Applications for M4 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)
M4 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037) are commonly specified for electronics, PCB hardware, optical mounts and small-scale machinery.
Mating Parts for M4
For M4, pair with a M4 hex nut (ISO 4032 / DIN 934) and, where used, a M4 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.
When to Step Up or Down from M4
When the joint preload approaches the proof load of M4 class 8.8, step up to M5 class 8.8 (or move to M4 class 10.9). When the joint is over-specified, M3 often saves weight and cost without losing the safety margin.