Hi thanks for the reply, but I have a cbeam machine a Sphinx and a mini mill and i have everything very tight and secure but this is my first time dealing with a belt driven system, i have is this one the 14t timming pulley gt2m timming belt the assembly video the person used a 16t timming or maybe my step jumpers are wrong, but squares and other shapes are ok i think.
what you show in the pictures is definitely backlash. make sure that one of the set screws on each pulley is resting on the flat on the motor shaft. make sure the setscrews are tight but have not stripped the threads. make sure the eccentric nuts are correctly set
no eccentrics, but it does have adjustment slots. if there is play in one side then the X can tilt as it moves....