Press fit knob for a 1/4” potentiometer shaft. Nice replacement for those cheap plastic lamp dimmer knobs  

Raw brass and steel.  Nice and heavy, feels good in your hand
I've seen them used for volume control on radios and guitars  

Details: 

•  Custom engineered lamp parts
• Intended for a 1/4in. ribbed dimmer Shafts
• The exact fit is 0.22" (fits your standard table lamp dimmers)
• Snug fit to hold the weight (use elbow grease or some heat to push them on)
  
  Add one of these industrial dimmer knobs to your next lamp creation

You can build it!