About this 3D model

I hab problems with z-axis wobble by printing with the Velleman K8200 printer. So i hade made some modifikation. First i had changed the solid coupler (z-axis and stepper-motor). With the new flex coupler i had the problem thad the z-axis holter starts to wobble. So i had made a new one to fix this. Now the printer works correct. For mountig you need 2x M5x10mm and 1x M5x16mm