A cam is mounted on a shaft by means of what?

The correct answer is the key, which serves a crucial purpose in securing the cam to the shaft. A key is a small piece of metal that fits into corresponding grooves on both the cam and the shaft, ensuring a tight fit and allowing for the transfer of torque. This connection prevents relative rotational movement between the cam and the shaft, which is essential for the cam’s proper function in driving mechanisms such as followers.

While pins, clamps, and nuts can be used in various mechanical applications for secure attachments, they do not provide the same reliability and effectiveness for securing rotational components as a key does. Pins may offer a form of alignment but do not guarantee the same torque transmission. Clamps may not provide a precise fit needed for components that rotate together. Nuts are typically used to secure threaded connections but lack the design to engage both parts in a way that effectively transmits rotational forces. Thus, a key is the most suitable option in this context for mounting a cam on a shaft.