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.
if my calculations were correct, 3 3/4 inches is 9.525 cm, and 1 1/4 inches is 3.175 cm.
So I rounded it accordingly to 10cm and 3cm.
If this is correct, then I'm happy to announce that the spool holder handle, which fits your spools, is uploaded!
Please report if it suits your needs and please share your results with hitting the "Post a make" button.