MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Yes, that is probably too tight for the motor shaft. Also try to get the belt into one layer.
And most of all, put the belt on after the nuts are tightened otherwise the front and rear legs won't be perpendicular to the table. Make the frame square, tight and then put the belt on.