As a general public service announcement...
Yo can search online for the material in question and get both an inside diameter and outside diameter.
For example: Conduit Size
I just googled EMT OD. This comes in handy quite often. When I built my frame I wanted to make it a breakdown, so I looked up the ID of 1 1/4" schedule 40 aluminum pipe and then just ordered a 2' chunk of the correct size round stock and drilled it out myself.
NRS breakdown side rail are $300 and I built mine for well under $100. That included the tube, pin stock, stainless hardware, and a new drill bit.
Post a picture of your table when you get it done, I love this stuff