Building the Y-Axis
is this normal? Everything seems to be aligned, all 4 corners are stable, belt is taught but it does this. Is it binding? I'm not pushing hard, very gently.
RE: Building the Y-Axis
Use process of elimination, what happens if the belt is off? Also try loosening the nuts on the ubolts.
RE: Building the Y-Axis
You are feeling the resistance of the stepper motor. As GKMAKEIT suggested, when you take off the belt you will notice all that resistance goes away. There are magnets in the stepper motor that are coming into and going out of position with the motor rotor and that creates the resistance. By the way when you move any stepper motor like that, you are actually creating voltage at the coil outputs. That can damage your electronics, so be careful not to do that when you are all hooked up without doing a motor off command first.
RE: Building the Y-Axis
You might want to make sure that the bolts on the bearing retainers aren't too tight. Overtightening them can cause the bearings to bind.