In order to achieve the high level of precision required, steel shaft manufacturers often use a process called turned, ground and polished.Turned:
Multiple passes may have to be made with the cutting tool depending on how oversized the rod is.
Although the rod now looks straight, concentric and smooth after being turned, it is not yet ready to be used as a precision shaft. Its surface condition is still relatively rough
to help it achieve the precision required. Once the dimensions of the rod are acceptable, it is then polished using a polishing wheel.
This polishing process gives it the smooth surface finished required. Once this step is complete, the metal rod is now considered a turned, ground and polished shaft.
It is worth mentioning that shafts can also be drawn, ground and polished. This process is almost entirely the same as turned, ground and polished, but with one major difference.
Instead of turning the metal rod down prior to grinding, it is simply cold drawn down to the required size, then ground and polished. With certain metals,
this process can allow for increased mechanical properties due to the cold work that is done to the rod during the drawing process.