Boring versus drilling — primary purpose of boring Compared with drilling, what is the main purpose of a boring operation on a previously made hole?

Introduction / Context:
Drilling initiates a hole; boring refines it. In process planning, boring is used after drilling or casting to achieve an accurate diameter, better roundness, alignment, and improved surface finish, especially on precision bores such as bearing seats.

Given Data / Assumptions:

• A pre-existing hole from drilling, casting, or core.
• Single-point boring bar in a lathe, boring mill, or machining center.
• Need for both size control and geometric accuracy.

Concept / Approach:
Boring removes additional material from the bore wall to reach the target size and straightness. Unlike reaming (mostly sizing/finishing with small allowance), boring can correct location errors, taper, and out-of-round conditions while enlarging to specification.

Step-by-Step Solution:
Identify starting condition: an existing hole.Define action: remove material from the bore to increase diameter.Outcome: improved size, straightness, and finish.

Verification / Alternative check:
Inspection after boring typically shows improved cylindricity and alignment compared to the as-drilled hole.

Why Other Options Are Wrong:
Drilling is for solid stock; finishing without enlargement is more akin to reaming/honing; purely ‘‘correcting’’ without enlargement is uncommon because some stock must be removed to correct errors.

Common Pitfalls:
Confusing boring with reaming or honing; each has specific stock allowances and achievable tolerances.

Final Answer:
To enlarge the existing hole (and improve accuracy/finish)