Master flange assemblies are disclosed herein. In one embodiment, a master flange assembly includes a master flange and a tube. The master flange includes a central aperture, at least one through-hole, and a plurality of cavities. The tube is arranged to pass through the central aperture and form the master flange assembly when secured to the master flange. In one embodiment, the plurality of cavities are recessions formed in a first surface of the master flange, wherein the recessions do not pass through the master flange. In one embodiment, the plurality of cavities are separated by ribs. In one embodiment, the master flange includes a shoulder recessed from a second surface of the master flange and adjacent to the central aperture. The tube includes a rim that engages the shoulder of the master flange when the tube is secured to the master flange to form the assembly.