Geometry of oblique cutting In oblique cutting of metals, how is the cutting edge oriented relative to the direction of tool travel (feed direction)?

Introduction / Context:
Cutting can be classified as orthogonal or oblique. The classification depends on the angle between the cutting edge and the direction of tool travel (or cutting velocity). This has major implications for chip flow and forces.

Given Data / Assumptions:

• Single-point cutting on a lathe or shaping machine.
• Conventional definitions of orthogonal vs. oblique cutting.
• Ignore tool nose radius effects for classification.

Concept / Approach:
In orthogonal cutting, the cutting edge is exactly perpendicular (90°) to the direction of tool travel. In oblique cutting, the edge is inclined at an angle less than 90°, producing a sideways chip flow with a component along the cutting edge, reducing chip thickness and distributing load.

Step-by-Step Solution:
Identify orthogonal condition: edge at 90°.Recognize oblique condition: edge angle < 90° to travel.Select the option describing an inclination less than 90°.

Verification / Alternative check:
Chip flows at an angle to the normal plane in oblique cutting, observable in turning with a lead/approach angle < 90°.

Why Other Options Are Wrong:
(b) describes orthogonal cutting; (c) is an extreme not representative of stable cutting; (a) relates to work axis, not tool travel; (e) is a restatement of orthogonal geometry.

Common Pitfalls:
Confusing approach angle terminology; ensure the reference direction is the tool travel/cutting velocity.

Final Answer:
Inclined at an angle less than 90° to the direction of tool travel