This is a removable turn knob, inspiration was for it to be used on a steampunk lamp dimmer or control panel. It is constructed in solid raw brass and made to slip over a 1/4" shaft, which secures nice and tight with the set screw.  

Details:
 

• Custom engineered lamp parts
• 2.5" Wide
• 1/4" shank attachment with set screw

*NOTE: This listing is for 1 knob. Additional items are shown in pics for sample purposes.