LIMNMEDIA - Rotation Stage Detail & Upright Pilot Hole

This marks the transition from the base rotation system into the vertical structure of the crane.

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Process

With the full stack assembled, the rotation stage is now visible as a distinct component within the system. The zinc-coated bearing sits between the adapter plate and the top plate, allowing the upper structure to rotate relative to the sled.

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On the top plate, a pilot hole has been drilled to establish the center point for the upright shaft. This shaft will support the jib arm and define the vertical axis of the crane. The hole is still in its early stage—just a pilot—but it sets the position for all subsequent drilling, reaming, or fitting operations.

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Notes

Seeing the bearing clearly in this stage helps confirm how it integrates into the stack. The contrast in material finish makes it easy to identify, and you can start to read how the load will transfer through it.

The pilot hole for the upright is more than just a starting point—it locks in the location of the crane’s vertical axis. Because it’s referenced from the same center used throughout the pulley and rotation stack, it keeps everything concentric.

As with earlier steps, starting with a clean, accurate pilot hole is critical. This is the reference that larger tools will follow, so any error here carries forward into the final fit of the shaft.

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LIMNMOCO Context

This step introduces the next axis in the system:

• The rotation stage defines movement in the horizontal plane
• The upright shaft establishes the vertical structure
• The jib arm will extend from this point outward

Everything is now organizing around a shared center:

the rotation axis becomes the foundation for the entire crane geometry

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Why This Matters

The upright shaft is the link between the base and the rest of the crane. If its position is off-center or misaligned, that error propagates into:

• arm balance
• motion arcs
• load distribution

Because the pilot hole is tied to the same center used for the pulley and bearing, it ensures that the vertical and rotational axes remain aligned. This is essential for smooth, predictable motion.