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 thought about making one with one screw hole but decided not to do so. I thought that it might bind the nut and screw rod.
The open loop is a good idea. I just hope that it is not too weak and break off if the spool bounces and jerks the filament or pops out.
That is the good thing about all of this to each his own. What is a good idea to one is not for others and you can always make changes to suit your needs. That is one reason why I made a variety of versions of mine. As always thanks.