Metal finishing is generally the last step in the fabrication process before shipping the part or sending it to an outside process. It involves using machines or hand tools to create a uniform surface.
Grinding is the process of using abrasive discs to create a uniform flat surface. Electric and pneumatic grinders are used to remove excess weld then an orbital sander finishes the surface so that a coating process can easily cover it.
Graining is the process of using a light abrasive belt in a large belt machine to apply a uniform surface grain. This is normally used on stainless and gives the same finish you would see on kitchen appliances.
Polishing is the process of using a cloth wheel spinning at high speeds in order to create a mirror like finish. This time consuming process is very visually appealing.
Tumbling is the process of placing small parts in a tub of vibrating ceramic material. As the triangular rocks vibrate they are able to remove sharp edges from the metal.
Sandblasting is exactly what the name describes. Parts are place in a sealed cabinet and air is used to shoot small sand particles at the surface of the material. This process can be used to remove surface rust or give a light dull finish.