Eyebolt Design - Lifting Points for 15kg+ Parts

Lifting point design for 15kg+ parts, center of gravity calculation, spot facing, thread depth

Rotating parts in CAD is easy. Manually moving dozens of kilograms of steel is not. Parts exceeding certain weight thresholds require lifting points for crane or hoist handling.

1. When to Add Eyebolts (15-20kg Threshold)

Safe manual handling limit for repeated lifting: ~15-20kg for adult males.

Practical Tip: Parts exceeding 15kg require eyebolt taps—no exceptions. "They can probably lift it" thinking leads to workplace injuries.

2. Locate at Center of Gravity (CoG)

Random eyebolt placement causes parts to tilt or spin during lifting, endangering nearby workers.

Practical Tip: Use CAD CoG calculation. Position eyebolt directly above center point for level lifting. Large/asymmetric parts need 2-4 eyebolts for balance.

3. Installation Details

Spot Facing: Eyebolts must seat flush for rated strength. Machine flat bearing surfaces (spot facing) on rough or angled surfaces.
Clearance Check: Verify no interference when installing eyebolt, and adequate overhead clearance for hoist hook access.

4. Deeper Thread Engagement

Eyebolts bear entire part weight. Design conservatively: minimum 2× diameter thread depth. For aluminum, use helicoil inserts or significantly increased thread depth to prevent pullout.

💡 Expert Advice
"An eyebolt hole is a small detail to designers but a lifeline to workers. When designing heavy parts, always ask: 'If I had to lift this myself, where would I grab it?'"

Lifting Eyes — US OSHA Compliance

Lifting eyes for overhead crane operations in US workplaces must comply with OSHA 29 CFR 1910.184 (slings) and ASME B30.26 (rigging hardware). Forged eye bolts per ASME B18.15 and Crosby G-291/G-292 are the US standards; DIN 580 forged eyes are accepted if ASME-equivalent strength is documented. Annual inspection by a qualified rigger is mandatory — log inspection per ANSI/ASSE A10.13.

Swivel Hoist Rings

For angled lift loads (>0° from vertical), swivel hoist rings (Crosby HR-125, RUD VRS) maintain full WLL through 180° rotation. Standard eye bolts derate dramatically at angles — 30° lift = 50% WLL, 45° = 25% WLL per ASME B30.26. Always use swivel rings for off-axis lifts. Stamp WLL must be visible after installation; obscured stamps require immediate tag-out.