Parting-off tool geometry in turning In lathe operations, the width of the cutting edge (blade) of a parting-off tool is typically selected within which standard range to balance chip flow, rigidity, and power requirement?

Introduction / Context:
Parting-off (cut-off) is a common lathe operation used to separate a finished component from bar stock. Choosing the correct blade width is essential for process stability, chip evacuation, surface finish, and tool life. Too wide increases cutting power and heat; too narrow risks chatter and tool breakage.

Given Data / Assumptions:

• General-purpose engine lathe with standard toolholders.
• Conventional HSS or carbide-tipped parting tools for steels and nonferrous alloys.
• Industrial practice and catalog ranges for typical parting blades.

Concept / Approach:
The blade width determines chip cross-section and stiffness. Common shop practice uses narrower blades for small diameters and softer materials, and wider blades for larger diameters requiring greater rigidity. Standard commercial blades for general work center around a few millimeters up to about a centimeter. The widely cited practical range is approximately 3 to 12 mm for typical lathes and work sizes.

Step-by-Step Solution:
Relate cutting force to chip cross-section: wider blade → larger chip area → higher force.Relate rigidity to width: wider blade → stiffer but more power needed; balance is required.Survey typical catalog sizes and shop norms → commonly 3–12 mm covers most standard turning jobs.Therefore, select the standard range 3 to 12 mm as the best answer.

Verification / Alternative check:
Tool catalogs list parting blades in roughly this range for general-purpose applications; very small precision lathes use narrower inserts, while heavy parting on large diameters may use special wider blades outside everyday practice.

Why Other Options Are Wrong:

• 5 to 20 mm (B) and 8 to 30 mm (C) are skewed too wide for typical lathes; they imply excessive power and slot width.
• 15 to 40 mm (D) is unrealistic for standard parting operations.
• 2 to 6 mm (E) is too narrow to represent the full practical spread across general-purpose work.

Common Pitfalls:
Using a blade that is too wide for small parts, causing chatter due to excessive force; or using too narrow a blade on large diameters, causing deflection and breakage. Ignoring the machine's power and rigidity limits is another common mistake.

Final Answer:
3 to 12 mm