You set up your machine, turn on the motor, and grind the valve. You are expecting a mirror-like finish. But when you pull the valve out, it looks like the surface of a vinyl record. It has tiny waves, ripples, or rough lines across the face.
In the machining world, we call t...
If you were building a door for a house, you would want the edge of the door to be perfectly flat, and the door frame to be perfectly flat. If they match exactly, they close tight.
In engine repair, you might think the same rule applies. If the valve seat is cut at...