I have not yet made a working radiometer, but I have revived the project, crafting vane assemblies and wanting to quantify them to compare their relative masses.  After weighing one of my spindles on a kitchen scale, and then a postal scale, and finding them both reporting zero grams, I realized I needed something better.  I went to my favorite source of cheap but valuable scientific equipment, the UMN Re-Use Center, a place where the various university departments deliver their old-generation equipment that has been replaced by the latest technology.  The old technology is still amazing, and I have benefited from it, previously acquiring a high-power Ortholux microscope and other items for a fraction of their market value.