Identify the hole-enlarging operation Evaluate the statement: “An operation of enlarging the end of a hole cylindrically is known as grooving.”

Introduction / Context:Different hole-related machining operations have precise names because they produce distinct geometries for fasteners and fittings. Using the correct term avoids ambiguity in drawings and process plans.

Given Data / Assumptions:

• Cylindrical enlargement at the end of an existing hole.
• Standard shop operations: counterboring, countersinking, spot facing, and grooving.

Concept / Approach:Counterboring creates a larger cylindrical section at the hole mouth to recess bolt heads or seat washers. Grooving usually refers to producing a narrow channel (on OD, ID, or face), not a cylindrical recess at a hole entrance.

Step-by-Step Solution:Identify desired geometry: cylindrical enlargement at the hole entrance.Map to processes: counterboring matches; grooving does not.Hence, the given statement is incorrect.

Verification / Alternative check:Machining handbooks show counterbore tools with pilots for concentric cylindrical recesses; “grooving” tools are different and used for rings, snap rings, or reliefs.

Why Other Options Are Wrong:Grooving is unrelated (C, D, E). Countersink produces a conical recess, not cylindrical.

Common Pitfalls:Using the term “counter-sinking” when a cylindrical recess is intended; confusing face grooving with spot facing.

Final Answer:Incorrect