I recently bought a Draper 50021 Belt Sander and found that the dust extractor port was far too big to mate up with my Henry Hoover vacuum hose. The sander port was 63mm in diameter whereas the vacuum cleaner hose nozzle was 32mm. I therefore decided to 3D print an adapter since I couldn't find one that had already been designed.
This was designed in AutoCad 123D Design, imported into Cura for slicing and printed on a Turnigy Fabrikator.
If you print one please note that the opening at the belt sander end is very slightly oversize. This was done deliberately to allow for a layer of tape to be wrapped around the outside of the sander nozzle in order to make for a snug fit. The first one I created was the same size as the nozzle which made it rather difficult to keep on.