I think Kenwood must have a knob fetish. They were really pushing the TS-590 in Dayton -- you couldn't walk through their area without being forced to take a glossy, detailed, thick brochure/booklet about it. It goes into great detail about the new features.
A whole page is devoted to the Main Control Knob.
Each of the aluminum parts is machined with CNC (Computerized numeric control) and treated with spin finish. We also paid careful attention to the color of the main control knob; we have colored the knob with a color alumite treatment.
We made samples repeatedly until the desired color was finalized. The alumite color is adjusted to match the rubber color of the knob ring [got a knob ring?] and the paint color of the front panel in order to express the integration and massiveness of the entire panel.