What is the "maximum working radius" of a crane, and how does it differ from "minimum working radius"?

The "maximum working radius" (also called maximum outreach) is the maximum horizontal distance from the crane’s rotation center to the hook when the boom is fully extended (under specific boom length and lifting height). It determines the crane’s ability to reach distant loads (e.g., lifting materials to the edge of a tall building).

The "minimum working radius" is the shortest horizontal distance from the rotation center to the hook when the boom is retracted or adjusted to the smallest angle. It is critical for operations in narrow spaces (e.g., lifting loads inside a small workshop), as a smaller minimum radius means the crane can work closer to obstacles without collision.

Notably, as mentioned earlier, the crane’s rated lifting capacity decreases as the working radius increases—so a crane may lift 50 tons at a 5m radius but only 10 tons at a 20m radius.
 

For excavators, what does "maximum digging depth" mean, and how is it used in project planning?

Maximum digging depth refers to the maximum vertical distance from the ground (in the equipment's standard working posture) to the lowest point the excavator bucket can reach when digging downward. It is a core parameter for determining the excavator's suitability for deep excavation tasks:

For projects like foundation pits, underground pipelines, or river dredging, the excavator's maximum digging depth must be greater than the required excavation depth (e.g., a foundation pit requiring 6m depth needs an excavator with a maximum digging depth of at least 6.5-7m to account for edge slopes and bucket tilt).

If the required depth exceeds the excavator's maximum digging depth, auxiliary measures (e.g., digging in layers, using a longer boom attachment) may be needed—but this will reduce efficiency, so matching the excavator's depth to the project's needs is key to cost-saving