I had an overhead dust collection system installed which did not come with suitable hoses for hand tools. The outlets were just those variable diameter attachments you hose clamp any sort of ducting to and reduced a 100mm duct down to about a 25mm hole without any streamlining.
After retrofitting something that would accept our usual Festool sander hoses, the air flow was much less being around 35m/sec. Much less than using a portable vacuum extractor.
I took some basic measurements and sketched this up in onshape. The result works perfectly and allows fast removal of the Festool hoses if they are needed at another station. Air flow has increased to 75m/sec
I plan on making several iterations of this, adding a slight taper and a self-closing flap will shut off the outlet when a hose is removed. However for now it is fully functional and solves the immediate problem.
Position the model so the 100mm opening is on your bed. I just printed it in PLA but I made the walls 5mm thick so it seems to be extremely strong.
Specific settings I used:
Bambu PLA Basic White
3 wall loops
5 bottom shells
5 top shells
20% infill
Inner/Outer printing order for the bottom 10mm, then Inner/Outer/Inner
The author marked this model as their own original creation.