Shortly said, what You have to do:

-cut all the tubes to their length dimensions

-weld them together

-turn the rotary parts (such as housings and shafts) on a turning lathe

-make the flat parts (laser cutting best)

-obtain a few standardized parts ( screws, circlips, a motor, microswitches)

-assembly all together

So, a lot of work, but the result is itworth, IMO.