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.
Where in the world did you find M13 nuts and bolts? I've checked every industrial supply I can think of; they all go from M12 to M14.
While it's a small list, if you could include a BOM with the links, that would be amazing for those of us who, apparently, lack the prerequisite Google Fu skill to find Jack and/or Schitt. I also cannot tell what length bolt you've used, so the BOM would help in that, too. It would also allow me to make sure that my weights are as equal to yours as possible, which would make it easier to trouble shoot later.
Thanks for your time, I love this design. Way more repeatable than a printed spring, and way cheaper than a custom wound metal one. In fact; as long as gravity doesn't go away or change drastically, it should be relatively repeatable for at least a few billion years!