Process sequence in hole making Considering typical workshop practice, which operation is performed first when producing an internal thread in a solid workpiece?

Introduction / Context:
Internal threads are commonly produced in blind or through holes. Understanding the correct operation sequence ensures dimensional accuracy and prevents tool damage.

Given Data / Assumptions:

• A solid workpiece requiring an internal thread.
• Conventional manual or CNC operations.
• Standard tools (drill, countersink/spotface, tap, reamer if needed).

Concept / Approach:
The usual order is: pilot/size drilling → optional countersink/spotface → tapping. If high precision is required before tapping (for thread class or alignment), reaming may be used to bring the hole to a precise size for forming threads (for thread-form taps or special processes), but for cut taps the drill size itself is chosen per thread chart. Boring is typically used for enlarging or correcting alignment of an existing hole, not the first step in solid stock.

Step-by-Step Solution:

Verification / Alternative check:
Standard tapping charts list drill sizes first; production travelers typically schedule drilling before tapping.

Why Other Options Are Wrong:
Spot facing: usually follows drilling to create a flat seat around the hole.Boring: used to enlarge/true an existing hole, not to start from solid.Tapping: cannot precede drilling.Reaming: optional precision step, but not first.

Common Pitfalls:
Skipping countersink/chamfer before tapping can damage the first thread; using the wrong drill size leads to poor thread quality or broken taps.

Final Answer:

Drilling