Red Seal Machinist Practice Exam

What machining process would you use to create a threaded hole?

1. Drilling

2. Tapping

3. Reaming

4. Turning

The correct answer is: Tapping

The correct process for creating a threaded hole is tapping. Tapping involves cutting internal threads into a pre-drilled hole, which allows for the insertion of a screw or bolt that matches the thread specification. In this process, a tap, which is a specific tool designed with cutting edges that form the threads as it is turned, is used after a hole has been drilled to the appropriate size. The tap is rotated into the hole, where its threads engage with the material, removing material to create the exact shape necessary for the thread. Other options, while related to machining, do not produce threaded holes. Drilling is the initial step where a cylindrical hole is created, but it does not impart any threading. Reaming is used to refine the size and finish of a drilled hole, but it also does not cut threads. Turning is a machining process used primarily on a lathe to create cylindrical shapes and external threads, rather than internal threaded holes. Thus, tapping is the definitive method for creating internal threads in a hole.