Students will know more about machine tools such as lathes and mills when joining the I_ _ _ _ _ _ _ _ _ M_ _ _ _ _ _ _ class.

The words you're looking for are "Industrial" and "Machining".

Step by step:

1. Identify the context: The sentence is talking about a class that students can join to learn more about machine tools like lathes and mills.

2. Understand the function: The missing words refer to the name of the class.

3. Fill in the blanks: Given the number of blanks and the context, the words "Industrial" and "Machining" fit. Industrial Machining is a field of study that focuses on the operation of machine tools.

So, the completed sentence is: "Students will know more about machine tools such as lathes and mills when joining the Industrial Machining class."