Because I like to over-complicate things and have everything do everything, I have made a bunch of adapters so I can go from anything to anything. I designed and printed adapters to go from 6in DWV pipe and adapters as well as 4in DWV pipe and adapters to 6in, 4in and 2.5in gate valves:
6in to 1 - 4in and 1 - 2.5in gate valve.
4in fitting (a tee in this case) to 2 - 2.5in gate valves.
Also, designed and available, but not printed yet - an adapter that goes from a 4in gate valve to 2 - 2.5in gate valves. Basically the same as above, but it goes from the gate valve, not the 4in fitting.
A sleeve to go from a 4in fitting to a 4in gate valve.
An adapter to go from a Bosch 5in RO sander to 2.5in hose. Designed so the adapter stays above the sanding pad surface.
Also available, a 4in short extension long enough to put two 4in fittings together. I didn’t want to buy 10ft of 4in pipe for a 6in piece, so I designed one.
Here are all the designs I have so far, with more to be added.
Here are the gate valves I am using. The 2.5in is linked, but you can select the others there on the page.
If you want something designed, let me know and I’ll see what I can do.
Soon to be designed and printed a fitting to go from a 6in gate valve to 2 - 4 in gate valves.