Rectangular to Round Transition

[cwood3]

I am making good progress on my Tophat Separator. It's a basic 20" chamber I.D. to go on a 32-gallon plastic trash can. My plan is to build it with a 5" inlet as my largest machine port is 4". I am planning on a 5" outlet as well because it's feeding a HF 2-HP with a 5" inlet. I am basically copying Retired2's separator. I am a 2-car garage shop and plan to mount my system in a corner on the wall and attach a 5" hose to whatever machine I need to use.

I have not settled on a chamber height yet because I am having some difficulty figuring out the best way to obtain a "rectangular to round transition" that will mate up to a 5" hose. I have explored some of the online calculators that determine  rectangular duct dimensions for a given diameter, keeping in mind CFM and FPM. I like the dimensions that Retired2 used (5-7/8" x 3-7/8"). I guess my question is: Is there a good source for obtaining a transition piece that would have suitable performance? I really don't want to fabricate one. I have the Excel spreadsheet (I believe that RonS posted way back) and understand how to use it. I have AutoCAD, so making a pattern is a no-brainer. I just don't have a proper way to do the bends and make the seam. I don't mind paying a premium for this piece. Seems like after all these years of posts and people making tophats, that there would be a tried and true solution.

I'm wide open...........and thanks to all who contribute to this forum.

Curtis

[nucww]

You may find the size you need by looking up register boxes.  I got mine custom made (2015) from spiral Manufacturing but I could not find the page today to make a new order from. My collector is described in "HF DC spiral collector with flow redirection" and I had a 5" round transition to a 2"x10" rectangle.  The cost for a wide mouth and the transition with shipping was ~$90.  You may be able to find a local sheet metal shop to do it.

[cwood3]

Yea, I reckon' I'll end up bending my own. Better get the MIG machine dialed in...................

[DustySanders]

I had my local sheet metal fabricator make up one for me, and I think it cost about 45-60 dollars. It isn't as heavy-duty as the pieces I bought from Spiral Manufacturing, but it is just fine. The one thing I'd suggest is you try to get all of your pipes and fittings from the same source, so you don't have to spend as much time joining pipes and fittings that are of slightly different sizes. 

[cwood3]

That will be easy! One 5" hose........will reach all machines.