What does the acronym FN represent in machining terms?

In machining, FN stands for "Force fit." This term is used to describe a method of assembly where parts are pressed together with a significant force, resulting in a tight fit. A force fit is commonly used in situations where components need to maintain precise alignment and stability, which is crucial for the functionality of mechanical systems.

A force fit can involve the use of shrink fitting, where one part is heated to expand and then fitted over another part which is cooler, allowing for a very secure joint once the temperatures equalize. This technique is vital in applications where movement or vibration could lead to loosening if parts relied solely on adhesive or torque.

Understanding the term "force fit" helps in grasping how components are intended to interact within a machine and emphasizes the importance of tightly connecting parts for performance and durability.