[JerryBurks]

I'm a bit stumped why your resonance issues are so bad and at such a low speed?..............

I don't know either but then, this is my first project using steppers and all I know is from here and other internet places. First I thought this was just related to my funny torque test rig setup and it would go away on a real machine with friction and mass to move. But alas, it did not. Admittedly this is just one evening experimentation and only on the Y-axis but I could get it to stall reliably around 110-120 ipm (about 3 revs or 1200 half steps per second). I strapped the spare wheel of a car with approx. 30 pounds to the Y-sled and it did not make a discernible difference.

When accelerating very slowly I can see that the stall happens around 110 ipm. I tried accelerating faster up to 100 inch per sec^2 and it just makes it stall faster and I don't know exactly at which speed but the motor never gets through this range.

I am pretty sure I will get this under control. I might try a harmonic balancer or other viscous damper, rattler or whatever the recipes are. But for now I will just get one of the praised Gecko drives and hope it solves the problem without such band-aids. I did spend a while on the phone with Mariss @ Gecko and he was very convinced it will. Let's see.....