Machining is like playtime with tools, but for grown-ups. Imagine you have a piece of play-doh and you want to make a cool toy from it. You'd need to use some tools like scissors or a cookie cutter to shape the play-doh the way you want it. Machining is like that, but with metal or hard plastic instead of play-doh.
Instead of just playing, though, machinists need to make sure they do everything just right to make sure the metal or plastic is shaped correctly. They use tools like drills, saws, and lathes to cut, drill, and shape the metal or plastic. They pay close attention to things like how much pressure to use and what speed the tool should move at to make sure the metal or plastic turns out just the way they want it.
Machining is really important because it helps make all kinds of things, from cars to toys to medical devices. Machinists make sure everything is just right so that the things we use every day are made correctly and work properly.