Just got my dust collection 6" (sewer) PVC run done, have blast gates coming off the PVC 6" x 4" "wye" connections, and 4" flex hoses out to each tool. The next part I thought would be easy, but I don't want to order the wrong adapters.

Seems like none of the adapters I have found mention both the ID and the OD of the small end to go to the tools. I have 3 tools that have the same size dust collection ports (14" Ridgid bandsaw, 12" Delta disk sander, and oscillating sander from Ridgid) - they all have exactly 2-1/4" ID on all the ports, and are all approximately 2-1/2" OD.

The small hose that came with the Delta has 2-1/4" OD ends and fits perfectly in all 3 tools.

My first thought is that I want adapters as large as possible, to keep the air flow high. To me, that would mean using 2-1/2" ID adapters, and slipping them over my tool's ports. Am I thinking about that correctly, or does it really not matter?

All of the adapters I have found just say 4" to 2-1/2", or 4" to 2-1/4". They never say whether the size they are listing is the ID or the OD of the adapter, so I have to assume it is the OD they list.

Actually, the only 4" adapters I have found with a 2-1/4" OD end are the funky offset adapters, and long funnels (that require extra room on the benchtop.) Maybe that's all there is, but that offset design seems inefficient, and the long funnel, while fine for my bandsaw, will be a bit long for the benchtop sanders.

Here are the ones I found:
Offset reducer: http://www.woodcraft.com/Product/200...r-Fitting.aspx

Long funnel: http://www.woodcraft.com/Product/202...-4-x-2-14.aspx

I have seen nothing listed with a 2-1/2" ID (I have to assume all the 2-1/2" adapters list the OD.)

What works, and where do I get 'em?

Thanks,

Dennis