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 in a solid workpiece, a sequence of operations must be followed to progress from a solid state to a highly accurate, finished large-diameter hole. The logical sequence is explained below step-by-step:

1. Drilling:
Drilling is the primary machining process used to originate a hole in a solid material using a rotating tool called a twist drill. Because drilling is a roughing operation, the resulting hole may not have perfect circularity, alignment, or the required large diameter. Therefore, it serves as the starting point.

2. Boring:
Boring is the operation of enlarging an existing hole that has already been drilled. A single-point cutting tool is typically used in boring. This process is crucial for finishing a large diameter hole because it corrects any eccentricity, ensures the hole is perfectly straight and concentric, and enlarges the hole to a size just slightly smaller than the final required dimension.

3. Reaming:
Reaming is the final sizing and finishing operation. A reamer is a multi-fluted cutting tool designed to remove a very small amount of material (typically a fraction of a millimeter) from the pre-bored hole. Reaming does not correct the alignment or position of the hole, which is why it must follow boring. Its sole purpose is to provide excellent dimensional accuracy, tight tolerances, and a high-quality surface finish.

Thus, the sequence starts with creating the initial hole (drilling), enlarging and straightening it (boring), and finally finishing it to the exact size (reaming).