A blind hole is a hole that does not go all the way through the material, while a through hole is a hole that goes completely through the material.
Blind holes are typically used when the material being drilled through is too thick to create a through hole, or when the back of the material cannot be accessed.
A through hole allows for easier insertion and removal of fasteners or other objects, and also allows for easier cleaning and maintenance of the hole.
One disadvantage of a blind hole is that it may not provide as strong of a connection as a through hole, as the threads of a bolt or screw may not go as deep into the material. Blind holes may also be more difficult to tap and thread.
Generally, a through hole is considered better for structural integrity as it allows for a more secure and deep connection between materials. However, the specific needs and circumstances of a project may require the use of a blind hole. It is important to carefully consider the design and function of the hole before deciding which type to use.