Boring machine kinematics: In which machine does the work remain stationary while the tool rotates during boring?

Introduction / Context:
Boring enlarges and finishes existing holes. Depending on machine type, either the work rotates (as in vertical turning/boring mills) or the tool rotates while the work stays stationary (as in jig and many horizontal boring machines). The question asks for the machine that clearly uses a rotating tool with a stationary workpiece for precision boring.

Given Data / Assumptions:

• Typical industrial configurations are considered.
• “Work remains stationary” means it does not rotate; linear feeds may still occur.
• Precision boring emphasizes positional accuracy and hole quality.

Concept / Approach:
Jig boring machines are designed for high positional accuracy using precise leadscrews/measurement systems. The spindle with the boring tool rotates; the work is clamped to a coordinate table (non-rotating). This matches the condition in the question most unambiguously.

Step-by-Step Solution:

Verification / Alternative check:
Machine catalogs show jig borers with precision coordinate tables; VBM specs show rotating tables carrying the work.

Why Other Options Are Wrong:

• Vertical boring machine: work rotates on a large table.
• Horizontal boring machine: often the tool rotates, but configurations vary; the question seeks the precision case—jig borer.
• Precision boring machine: generic term; jig borer is the specific, standard answer.

Common Pitfalls:
Assuming “stationary” excludes linear feeds; here it means no rotation of the work.

Final Answer:
Jig boring machine