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.
I stopped when it was clear the screw wasn't going to have enough vertical height to meet the top part of the arm. I've since ordered a bunch of M3 socket head screws and will revisit this. Meanwhile I'm using the stock arm on your printed base and things are working. I've also picked up an aluminum extruder assembly but haven't yet needed to use it. I'm a big fan of "if it ain't broke, don't fix it" when it comes to new gizmos. My original problem may have been a clogged nozzle and possibly the heatbreak. I've since changed both of those too.
I wasn't happy how my Mini printed out your small cover portion for your arm design. I may reprint it before trying again.