I made you three different versions. I made two flush-mount versions that will seat onto the motor shaft right up to the gearbox and end at the end of the shaft. One is ‘wide’, meaning the hole is 6mm diameter instead of the specified 5.98mm (Hopefully pictured above if my facepunch tagging isn’t rusty). The other has the wide hole with the same height as the original model. The one you’ll likely end up using is the original, wide file. I also left the raw freecad files in there so you have the uncompiled meshes if there needs to be any other changes. I tried to upload it to tinyupload, but google said the file was then malicious when I tested it, so whatever. Don’t worry about paying me; I feel like I needed some CAD practice anyway. I can’t guarantee they’ll exactly fit the beads either, since I’ve never made a bead chain gear before. PM me your email and I’ll send them over.
Also my brother is yelling at me to hang out with him, so I might take a bit to get back to you.