This is an adapter for the Flashforge Adventurer 3. It slides into the center pin of the existing mount and adapts to +50mm spool center sizes. I built a hinge so that you can still take advantage of the filament run-out switch even with the larger size spools.
Edit 2018-12-09: Added new style connector and pin file, this one can be printed upside down and requires no support.
Works like a charm!
I printed this with 4 shells for extra rigidity.