Which tool is used to cut internal threads on an object?

• A. Reamer
• B. Hammers
• C. Taps
• D. Dies

Answer: (C)

To create internal threads inside a hole, you use a tool designed to cut threads on the inside surface: a tap. You drill a hole to the appropriate size, then use a tap (often with a tap wrench) and rotate it to cut the internal spiral ridges. Cutting oil or lubricant helps the tool cut smoothly and clears the metal swarf as you go. Taps come in various pitches and lengths to match the desired thread, and you may need different types (taper, plug, or bottoming) depending on how deep the threads are.

A dies cuts external threads on the outside of a rod or bolt, so it wouldn’t create threads inside a hole. A reamer enlarges and smooths an already drilled hole to precise dimensions, but it doesn’t cut threads, and a hammer isn’t a threading tool.