Machine tool design comparison For machines of the same size, which statement about a plain (horizontal) milling machine versus a universal milling machine is generally true?

Introduction / Context:
A plain (horizontal) milling machine is designed for rigidity in slab milling and heavy stock removal. A universal milling machine adds a swiveling table and other mechanisms to enable helical milling and multi-axis setups, often at some cost to stiffness and mass for a given size.

Given Data / Assumptions:

• Comparing machines of the same nominal size class.
• Universal adds flexibility (swivel table), not necessarily rigidity.
• Focus is on general construction and stiffness.

Concept / Approach:
Additional articulations in universal mills introduce more joints and overhangs. Plain mills concentrate mass in a simpler column–knee–table system, usually giving higher rigidity and weight for heavy horizontal arbor work.

Step-by-Step Solution:
Identify design differences: swivel table, gear trains for helical milling (universal).Assess impact: more versatility but slightly reduced stiffness/weight for same size.Conclude the statement that plain mills are more rigid/heavier is generally correct.

Verification / Alternative check:
Manufacturer catalogs list machine weights: plain versions typically weigh more than universal counterparts in the same size range.

Why Other Options Are Wrong:
“Incorrect” contradicts common design practice. Limiting validity to CNC or small benches is unnecessary; the principle holds broadly.

Common Pitfalls:
Equating versatility with rigidity; in milling, rigidity is paramount for finish and tool life when using large slab cutters or wide face mills.

Final Answer:
Correct