So I'm making a eSpinner but along the way I wanted to test my Bobbin design. The idea here is that I would make different end caps to have a very good fit on each shaft size. The first one I'm uploading is a 6.75mm shaft size that works with an Ashford Kiwi spinning wheel.
So print 2 of the adapters, one for each end and then just one of each of the other parts.
You do need to glue one side of the bobbin on after printing as that was just easiest for me, the end caps that can adapt the shaft size seem to stay in ok on their own.
There's a chance if you don't do a super job gluing it that you get a tiny wiggle, but in our case it wasn't enough to cause issues as the whirl on this spinning wheel has a more obvious wiggle.