When selecting holes for fastening with bolts, which option is preferred?

• A. Bolt holes
• B. Screw holes
• C. Tapped holes
• D. Blind holes

Answer: (A)

The main idea is to use holes that let the bolt’s shank pass through freely to allow easy assembly and proper clamping with a nut or a threaded counterpart. When you fasten with bolts, you typically pass the bolt through a clearance hole in one piece and then secure it with a nut on the opposite side (or into a tapped hole in the other piece). Using a hole sized as a bolt hole ensures the bolt fits without threading into the hole itself, preserving strength and allowing straightforward assembly.

Screw holes are meant for screws that cut or engage threads in the material, which isn’t how a typical bolt joint is arranged. Tapped holes are threaded holes that accept bolts by threading into the hole, which makes the joint harder to disassemble and can weaken the member a bit due to material taken up by the internal threads. Blind holes don’t provide access from the opposite side to tighten a nut, so they’re not suitable for through-bolt assemblies.