From the local hardware store, I bought steel tubes (3/4 inch) as table legs to store the filament. However, since all these tubes have right-hand threads, there's a problem when trying to screw them together in a circle. So I redesigned two parts to be able to turn the last piece simultaneously in both threads in a circular fashion. I also added the 90° connector with 2 right threads. Regular pipes can be found e.g. here (not my design): https://www.printables.com/model/1276995

Printed in PETG with support modifiers at the threads (in the pipe).