Where Should I Look for a 3.5" Diameter 2" Long Cast Iron Cylinder

I can and will cut it down to size.  I just cannot imagine that there is not a place that produces scraps about that size.  I need a 2 kg counterweight for an equatorial mount and the normal retail sources seem to have knotted up supply chains.  If I can buy American scrap, drill the counterweight shaft hole and drill and tap a thumbscrew hole, all the better.

Never mind. Adorama had it in stock.  I could have made it cheaper but money is less valuable than time.