I decided to bend a ring out of the piece of aluminimum slant to make the lens holder instead of using the cardboard tube. It is not competely round, but close enough.

I found a piece of aluminium for the camera mount. It was a leftover from an IKEA kitchen furniture module.

The two 10 mm tubes are 250 mm long and the 12 mm tubes are 35 mm. The 10 mm tubes slide nicely inside the 12 mm tubes.

The Idea is to bond the shorter pieces of tube to the ring I made with Epoxy. (If that is good enough for a race car it is good enough for me.) The ring will hold the lens. In this way I can move the lens back an forth for focusing and keep it perfectly aligned with the camera.

Next I need to get some epoxy…