The correct sequence of machining operations to be performed to finish a large diameter through hole is

The correct answer is drilling, boring, reaming.

To finish a large diameter through hole, a sequence of machining operations must be followed in a logical order based on the capability, accuracy, and purpose of each operation:
1. Drilling: This is the initial step used to create a preliminary hole in solid metal. Drilling is relatively fast but does not produce a highly accurate diameter or a smooth surface finish.
2. Boring: After a hole is drilled, boring is performed to enlarge the existing hole to a larger, more precise diameter. It corrects the alignment and concentricity of the drilled hole, which is essential for large diameter holes.
3. Reaming: This is the final finishing operation. A reamer removes a very small amount of material to bring the hole to its exact final size with tight tolerances and provides an excellent surface finish.