I made one. I used 1/2 aluminum round bar and 1/4 inch SS round bar for screws. Threaded all myself, and I used 3/4 inch pipe, which looks about the same as what’s in your pics.
It’s pretty harsh on the head of my penis! I would like to see pictures of people using one of these. I’m wondering if I’m doing it right! I just started but it’s a good stretch, if I use the bay are right afterwards there’s less that 1/2 inch remaining on the length