Trepanning operation — correct definition In hole-making, trepanning is best described as which of the following operations?

Introduction / Context:
Trepanning is a specialized hole-making method used to produce large-diameter holes efficiently by removing only an annular ring of material. It is common in plate fabrication and where core preservation is desired.

Given Data / Assumptions:

• Goal: create relatively large holes in plates, pipes, or solid stock.
• Tool: hollow, circular cutter (trepanning tool or hole saw) guided about an axis.

Concept / Approach:
Instead of drilling out the entire cross-section, trepanning cuts the circumference and leaves a solid core. This reduces power consumption and chips compared to drilling a full solid, and the slug may be reused as a blank.

Step-by-Step Solution:

Verification / Alternative check:
Power calculations show reduced torque for trepanning vs. drilling same diameter, validating the operational definition.

Why Other Options Are Wrong:
Spot facing and chamfering shape the mouth/surroundings of a hole, not through-hole creation. Reaming only sizes an existing hole. Tapping forms threads, not the basic hole.

Common Pitfalls:
Assuming trepanning equals hole saw use only; trepanning can also be performed on lathes and milling machines with dedicated tools and coolant arrangements.

Final Answer:

Producing a hole by removing material along the circumference using a hollow cutting tool