I have a Nexus 4, which I think is a great phone. I have it in a fairly reasonable hard aluminium case to protect it. Using a case is normally a good idea; however, the thing about most cases is that they are incompatible with a dock.
At this point I realised I needed a hole in each leg to take the threaded rod that drives the Y axis. No problem, some careful meassuring and drilling and presto. But now I realise my previous tightening of the bearings in place on the Y axis had left the central hole not quite central.