I am having a problem with my motors sticking or catching even when moving them by hand when powered down.
When I disconnect the motors from each other they run perfectly smooth which I think pretty much eliminates a mechanical issue, but when I wire them in parallel with the connector they start to stick every 10 mm or so. This problem persists when I run them with repetier through an arduino mega and RAMP 1.4 and DRV 8825 (recommended setup from the site.)
Could this be due to the mismatch in inductance for the two motors on the same axis? I would expect to see other people commenting on this if it was so.