All the mechanics is made of 3D printed pieces and some Stuff (like bearings and bronzine they can be easily find on internet).
Maybe the most expansive are the two 6204 bearings.
If you don't load too much the tracker you try do replace with a DIY thrust bearing.
The machine can be divided on 4 parts:
-You will need two bearing 6204, and mount them in the base_support (“base_bot_bearing_support.stl”)
Screw everything on piece of wood.
-Print the main base and fix it with top_support using screw in the predefinite holes.
-Put at least 2 M3 nuts per each hole of the frame two bronzines (8x10x12 in the biggest hole).
-Print all the necessary gears and fits in them two 623 bearings (where it needs), and just fix them on the frame with some m3 bolts.
-Mount the Nema motor using this printed pieces of plastics
-Mount on the main base
-Prepare the frame and the gears in the same way you made for the the other gearmotor.
The only difference is that you will need two 608 bearing instead of the bronzines.
-Take a smooth metal rod of 8mm of diameter and cut 4 pieces of 120mm of length.
-Make a little hole in them and use a tapping tool.
-Screw the 4 rods in the support as shown in the photo.-Insert two 628 bearings in the top_support and a 8x10x12 bronzine in the other.
-Place the springs in the rods. The right springs depends on the load of arm. I made calculus with a Matlab and for a load of 5Nm the best equivalent spring is about 750N/m (4x spring in parallel means (750/4)N/m each)
-mount everithing in the main base, paying attention to match perfectly the Elevation gearmotor and the the rod support.
I know it is a very simple guide and I will improve it with time with more photoes and maybe with some ISO technical drawing table.