I started this project because I needed the dust collector adapter model included in this post. If you're interested in that model only, you can go here for greater detail. However, as I designed the adapter in Fusion 360, I realized I could generate a fully parametric model that would let others customize their own rectangular to circular adapters for dust collection, HVAC, vent lines, etc.

The Parametric Model:

I have included both the Fusion 360 .f3d file and general .step file to use in whatever CAD program you might like. The model has User Parameters defined that enable changes to the following:

• Rectangular end length, width and height
• Rectangular end taper (inward or outward)
• Circular end diameter and length
• Circular end taper (inward or outward)
• Distance between the circular and rectangular fittings
• X and Y offset between the circular and rectangular fitting ends
• Wall thickness

The dimensioning is set up to be inputted as inside dimensions for the ends, but if outside dimensions are the critical measurements for your adapted, simply decrease the inside dimensions by 2 times the wall thickness you intend to used to get precise outside dimensions.

Example User Parameter windows and resulting models can be seen in the attached pictures. The model worked well to create a range of shapes, but I expect there will be limits. I am not a Fusion 360 expert, but can try to help if people run into issues.

If you want the adapter to have smoother corners, just add fillets or chamfers to outside and/or inside corners after all dimensioning is complete. Doing this prior to dimensioning may result in errors during dimensioning.

3D Printing Your Model

I chose the parameters for my dust collector shroud that allowed printing without supports, but every new adapted will need to be studied in your slicer to determine where supports might be needed. I also printed my model with a brim since the end face, at least in my model, did not have a significant amount of bed contact area.

I hope others find this useful.