What is the term for an axially located rectangular groove in a hub and shaft?

The term for an axially located rectangular groove in a hub and shaft is a keyseat. A keyseat is specifically designed to accommodate a key, which is a small piece of metal inserted into the groove to provide a secure connection between the shaft and the hub or other rotating component. This connection prevents relative motion between the two parts, ensuring that torque is efficiently transmitted when the shaft rotates.

Keyseats are critical components in mechanical design because they allow for easy assembly and disassembly of parts while maintaining a strong mechanical bond. They can be found in various applications, including gears, pulleys, and couplings.

The other options refer to different features that do not match the description of an axially located rectangular groove. A cotter pin seat pertains to a hole where a cotter pin is inserted to secure parts together but is not specifically a groove. Flutes are spiral grooves found on drill bits or similar tools for cutting purposes, and a set screw point refers to the end of a set screw that can engage with a shaft, not a groove. Thus, the keyseat is the most accurate term for the described feature in this context.