What is the term for the smooth part of a drill bit that fits into the drill's chuck?

The term for the smooth part of a drill bit that fits into the drill's chuck is known as the shank. The shank is typically cylindrical and designed to securely fit into the chuck of a drill, allowing for stable rotation and efficient drilling. It is the section of the drill bit that ensures a firm grip within the chuck, facilitating the transfer of torque from the drill to the bit itself during use.

Understanding the function of the shank is crucial for selecting the right bit for your drilling needs, ensuring compatibility with your drill type. The other terms listed, such as bit holder, collar, and shaft, refer to different components or aspects of drilling tools that do not define the portion of a drill bit designed specifically to fit into the chuck.