A lifting eye bolt — gb/t 825 / din 580 (series 037 in M20: this guide pulls the row from the standard, adds the assembly numbers an engineer actually uses, and links you straight to a quote.
M20 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 |
|---|---|---|---|---|---|---|
| M20 | 2.5 | 120 | 30.0 | 20 | 17.0 | ISO 4762 / GB/T 70.1 |
Spanner & Drive for M20 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)
The hex socket for M20 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 M20
| Coarse-thread pitch (ISO 724) | 2.5 mm |
|---|---|
| Through-hole / clearance (ISO 273 medium) | 22 mm |
| Tapping drill, coarse thread | 17.5 mm |
Tightening Torque for M20
| Class 8.8 (dry, ~µ 0.125) | ≈ 410 Nm |
|---|---|
| Class 10.9 (dry, ~µ 0.125) | ≈ 580 Nm |
| Class 12.9 (dry, ~µ 0.125) | ≈ 690 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 M20 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)
M20 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037) are commonly specified for heavy assembly and large machine mounts.
Installation Tips for M20 Lifting Eye Bolt — GB/T 825 / DIN 580 (Series 037)
- Use a quality Allen key fully seated in the socket — partial engagement is the most common cause of stripped sockets at this size.
- For countersunk and button-head variants, chamfer the through-hole to seat the head flush without preloading the head/shank fillet.
- At M20 the stretch in the bolt becomes the controlling factor — for critical joints, use angle-controlled or stretch-controlled tightening instead of pure torque.
Mating Parts for M20
For M20, pair with a M20 hex nut (ISO 4032 / DIN 934) and, where used, a M20 flat washer (ISO 7089 / DIN 125A) under the head and under the nut.