I have been sorting through this pile of reloading gear and one of the items is a (1978) Bonanza "Blue Ribbon Grain Scale". (Bonanza is now Forster) I was surprised to find that the scale is completely made of Lexan plastic but for the knives & their seats, the dampening magnets, the beam sliders and pan assembly. Bonanza took great pride in making their tools from high carbon iron castings so I was a little taken aback thinking that I could use it for some sort of rough bullet sorting work if nothing else. The Lee, at least, used an aluminum base. Curious, I trotted it down to the reloading room and matched it up against my hyper accurate Ohaus Dial-o-Grain dual beam, weighing a small lot of 22 Hornet cases. Each weight from the Bonanza matched those of the Ohaus to within a very small part of a tenth of a grain. Who'da guessed that??
Until i found this one, I would have bet that Lee was the first outfit to make a plastic/polymer beam scale. ~Muir