My unit lasted all of about 300 seconds of total operating time before seizing up. The load was all of 2 ounces, requiring 6 inches of travel. Worked fine the first day as I was assembling and testing. Then, coming back 3 days later to use it was totally locked up. I swapped in another NEMA17 stepper and that worked perfect, so my controls and electrical are all fine. I tried working the motor by hand once disconnected and, at first, it wouldn't rotate at all, Eventually, it began to rotate but See full review