There are two Base Bars in every Archivist scanner. They are made from 1/16 wall, 1.5″ square aluminum tubing. The base bars are symmetrical and have a 1/4 20 tube end connector nut from Carpin Manufacturing pressed into each end. They are secured to the Side Plates using 1/4 20 Furniture Bolts.
The picture on this page shows powdercoated Base Bars, but the scanner is designed so that they can be shiny, bare aluminum without any effect on the imaging module of the scanner. Kits shipped with unpainted bars; the bars do not need to be painted but occasionally may need to be cleaned.
PDF Drawing of part:
STL File of Part: