Which tool is used to cut internal threads in a hole?

• A. Dies
• B. Tap wrenches
• C. Reamers
• D. Taps

Answer: (D)

The idea being tested is which tool creates threads inside a hole. Internal threads are cut with a tap. A tap is threaded and shaped to cut into the interior walls of a drilled hole, forming the corresponding internal threads. You typically drive a tap using a tap wrench to turn it, and you apply cutting oil to aid cutting and chip removal. The other tools have different jobs: dies cut external threads on rods or bolts, reamers enlarge and smooth holes without creating threads, and a tap wrench is simply the tool used to turn a tap, not the cutting instrument itself. So, for creating internal threads, the tap is the correct choice.