8458.91.50.40 - Used or rebuilt

This HTS subcategory encompasses numerically controlled lathes that do not fall under any other specific numerical control designations within the broader category of "Other lathes." These machines are designed for metalworking operations where material is removed through the action of a cutting tool, and their operation is guided by pre-programmed numerical commands. The defining characteristic here is the absence of more granular sub-classifications for specific types of numerically controlled lathes, making this a residual category for such equipment.

To distinguish this from potential sibling categories, consider that other numerically controlled lathes might be classified based on specific features such as their primary method of control (e.g., digital readout systems that are not fully automatic numerical control), or their intended primary use if a more specific heading existed. However, within the current hierarchical structure, this category serves as the ultimate destination for numerically controlled metal-removing lathes that do not fit more narrowly defined subheadings.

As this is a leaf node in the HTS classification, there are no further subcategories. Therefore, the focus for classification within 8458.91.50.40 is on ensuring the item is indeed a lathe for removing metal, that it is numerically controlled, and that it does not meet the criteria for any other more specific numerical control-related subheading at this level. The "Used or rebuilt" designation further refines the classification to apply to these specific conditions of the machinery, rather than new equipment.