baseplate for 19mm tube

This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/1LUssAHV5tS

5mm bolt, 8mm nuts, washer printed to fit. I used it on 19mm plastic tubing to fit a metaldetector circuit on it. Weekend project with my son. SChematics attached...
the tubing is that yellow tubing used for wiring a house.

can also be used on bikes and the like. You can also alter the design, be my guest ;)