How does the TREX/MX400 head attach...

Maybe you can steal their idea.

I do know that the shaft on the 400 size heli's has a larger diameter, and maybe that is the problem we will just have on the cp pro...

The micro heli cnc main frame for the cp looks very cool... Just to expensive!

What if you ground an ever so small flat spot on the shaft on each side where the set screws hold onto it.