For holes that pass completely through the part, which hole type is recommended?

• A. Blind holes
• B. Counterbored holes
• C. Through holes
• D. Tapped holes

Answer: (C)

Holes that pass completely through a part are called through holes. This type is used when you need a feature that lets a fastener, pin, or other component pass from one side to the other or when access is required from both faces. Because it goes cleanly through the material without a bottom, it’s the natural choice for holes intended to extend through. Blind holes stop before the far side, counterbored holes create a recessed seat for a fastener head, and tapped holes are threaded. None of those match a hole that goes all the way through, so the recommended choice is a through hole.