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CGE conversion


Alexander Varakin
 

Hi All,

There are not many CGE mounts converted so far, so I decided to publish what I have done.
I used TMC2209 drivers at 16 microsteps, MKS GEN L 1.0 board, 400 steps NEMA 17 motors and 16 to 40 timing pulleys. 
The 40 teeth pulleys did not fit into the existing cavity, so I had to mill out some material in that area. The motors were also not fitting so I had to mill out some material in the motor cavity. 
Initially, I was trying to get away without disassembling the mount and milled out the material with only partial disassembly of the mount, but I severely conaminating everything with the AL chips, so I ended up disassembling and re-lubing the whole mount anyway. It turned out that disassembly is not as bad as I thought. 

I used 3mm AL plate for attaching the motors to the worm holders. I had to mill cavities in the worm holders to give space for screw heads.

MKS GEN L board, RPI4 and 12->5v converter are mounted on 1.5mm AL plate and the plate is attached to the scope.
The scope is 8" RC. 
I did some preliminary testing and guiding accuracy is below 1".
I recorded the tracking error using PHD and ran PHD log analyzer to find that I have about 12" amplitude of 480s periodic error as well as 2" of 480/2.5s error. 
I don't think that 480/2.5s error can be tuned out using PEC, so in hindsight, I should've used 15 to 30 teeth pulleys, that would also reduce the amount of milling.  
 

Alex


Khalid Baheyeldin
 

Nice conversion ...
Added to the show case. Thanks for sharing