Millwright Level 1 Practice Exam

What does the term "cutting speed" refer to?

1. The speed of the lathe

2. The rate at which the tool wears

3. How fast the workpiece travels past the tool

4. The feed rate of the tool

The correct answer is: How fast the workpiece travels past the tool

The term "cutting speed" refers specifically to how fast the workpiece travels past the cutting tool. In machining operations, cutting speed is critical because it significantly influences the efficiency of the cutting process and the quality of the finished product. It is typically measured in surface feet per minute (sfm) or meters per minute, depending on the system of measurement being used. When the workpiece moves at the appropriate cutting speed, it allows for effective material removal while helping to manage heat generation and tool wear. Proper cutting speed optimizes performance, leading to better surface finishes and extended tool life. In contrast, the speed of the lathe pertains more to the machine's rotational speed rather than the direct interaction between the tool and the workpiece. The rate at which the tool wears is more related to tool material and conditions but doesn't define cutting speed. The feed rate of the tool, which refers to how fast the tool advances into the workpiece, is also a separate parameter that works in conjunction with cutting speed but is not synonymous with it.