Bearing2Marble Adapter

thingiverse

This adapter allows you to swap out bearing weights with marbles, perfect for replacing them in your spinner if you have a stash of them lying around like I do. It's designed to accommodate marbles and ball bearings measuring between 14.5 mm and 16 mm in diameter - though the larger size might be a bit of a tight squeeze, and anything smaller than 14.5 mm will likely fall out. You can use this adapter with most standard toy marbles, even though they come in varying sizes and finishes at this scale. Just keep in mind that for the marble to fit snugly, the adapter shouldn't form a complete circle when assembled. Check your print settings for more information on how to get it just right.