The tube is a soil pipe, and machined parts were from MDF and turned on my woodworking lathe.
I've been making parts out of MDF for the past 25 years and have found it very stable so long as you seal
the edges and waterproof it.
For the focus mount I went a bit retro and used a very nice Japanese made rack and pinion unit.
For a couple of years now I've been making small tubes from bonded sawdust and wood chips
(the waste material from the wood turning) I used this method for the dew shield.
Finally got the project finished, and here are the pictues.
First off, the lens and cell.