Harbor Freight is a great store for the starting hobbyist. However, sometimes their tools come with limitations. In this case, I wanted to use their small shop-vac with a random orbital sander that they also sell. The only problem was that the hose from the vacuum does not fit the sander. A 3D printer and a set of calipers makes it super easy to remedy this situation. The model is designed with a snug fit in mind.
The model works as designed with my printer it's not uncommon to need to scale the model up or down a couple percent to get the best fit.
2-1/2 gal. Wet/Dry Vacuum/Blower | Central Machinery®- Item#61162
2.8 Amp, 5 in. Random Orbital Palm Sander | Bauer- Item#63999
Just orient the model so that the shelf is facing up to avoid the need for supports.