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.
Those are some pretty awesome looking keys. I'll draw them into my CAD program and see if there are any changes to make them fit.
That one little tab on the side of the key @6cm, you may want to file down a notch into the key holder. Another option in the meantime if you're impatient is to scale the keyholder in your Slicer program to 1.2 or larger and see if that changes anything for you? You would have to use larger bolts and nuts as well - maybe M4 or M5?