Superfinish
If it has to be really smooth.

Bearings, gears and other engineered components transmit energy and/or motion to the interface by rolling, sliding and rotating. Areas of metal-to-metal contact between components are of great engineering concern. Such contact points increase frictional resistance, resulting in premature wear and reduced efficiency.
With superfinish, these drawbacks are kept to a minimum. At Metalo we have superfinish equipment. With the superfinish technique material is removed by means of a polishing belt. Resulting in a super smooth suface.