Portable drywall sander hub assemblies with apertured backing assemblies

A backing assembly for a portable drywall sander hub assembly, comprising

• a backerplate including
• a mounting portion forming a threaded bore adapted to couple the backerplate to a fastener of a sander hub, the fastener of the sander hub protruding within a counterbore of the sander hub, and
• a backerplate body connected to the mounting portion and forming a plurality of backerplate apertures therein positioned radially between an outer circumference of the backerplate body and the mounting portion, the plurality of apertures being adapted for dust to pass therethrough and into a cavity, formed into the counterbore between the sander hub and the backplate body, during operation of a drywall sander with the backerplate mounted thereto;
• and
• an intermediate plate joined to the backerplate, the intermediate plate including an intermediate plate body forming a plurality of intermediate plate apertures therein, the plurality of intermediate plate apertures being sized and spaced to match and align with the plurality of backerplate apertures,
• wherein the backerplate and the intermediate plate are joined by fasteners, the fasteners including a first fastener attached to the backerplate and a second fastener attached to the intermediate plate, and wherein each of the first fastener and the second fastener includes a plurality of fastener apertures sized and spaced to match and align with the plurality of backerplate apertures and the plurality of intermediate plate apertures,
• wherein the mounting portion includes a front protrusion that protrudes in an axial direction of the mounting portion and protrudes relative to the backerplate body in the axial direction towards the intermediate plate, wherein the front protrusion is adapted to guide the intermediate plate into axial alignment with the backerplate, and wherein the intermediate plate forms an intermediate plate bore adapted to receive the front protrusion,
• wherein the mounting portion includes a rear protrusion that protrudes in an axial direction of the mounting portion and protrudes relative to the backerplate body in the axial direction opposite the intermediate plate, the rear protrusion adapted to ensure that the backerplate body is offset from an opposing axially facing surface of the sander hub, and
• wherein the plurality of backerplate apertures, the plurality of intermediate plate apertures, and the plurality of fastener apertures are adapted for dust to pass therethrough during operation of a drywall sander with the backerplate and intermediate plate mounted thereto.