Has anyone machined Steel with their CNC Router?

I am keen to make a CNC router mostly for working with Aluminium but would like to be able to do the odd bit of steel machining. All for hobby purposes so don't need production quality or speed.

I know this will be a difficult task so I am curious to know if anyone has pulled it off? and if so what configuration of machine was used - fixed or moving gantry, ball screws or lead screws, linear bearing used?, servo motors or steppers etc.

Brett

PS I know this forum is under the woodworking section but most of the CNC router experts seem to be here...