Tilarta wrote: ↑
Fri Oct 04, 2019 9:16 pm
I used Edit>Select All before exporting,
That's wrong and a common beginner mistake. By Exporting "All", you're also Exporting parts of your model that existed before the Chamfers, and these larger shapes fill in what the Chamfers removed.
Each of your swords are a bunch of disconnected pieces, usually we would join them together while building the model.
Press and hold the Crtl key, and from the history tree add each visible piece to your selection so that all the visible things (and only the visible things) are selected, then do your File > Export. For me the resulting .stl was about 35.2 MB.