Final answer:
To lock a part onto a shaft (option A) , a set screw is used. It provides clamping force to prevent movement between the component and the shaft, and is common in mechanical and engineering applications.
Step-by-step explanation:
To lock a part onto a(n) shaft a set screw is often used. The correct answer to the question is A) Shaft.
Set screws are designed to be inserted into a threaded hole on one component and tightened against another part, such as a shaft, to prevent movement between the two. The set screw exerts clamping force through its tip, which can be a point, flat end, or cup-shaped, directly onto the shaft, or onto a key that engages with the shaft. This is a common mechanical practice in machinery and various engineering applications, where maintaining the position of components on a shaft is critical.
Using set screws is one of the simplest methods of securing components like pulleys, gears, or collars on a shaft. They provide a balance between sufficient holding strength and ease of adjustability or disassembly when maintenance or alterations are required.