While looking for something else, I re-discovered this page on 6 mm reloadable sugar motors:
https://jcarter.privatedata.com/6mm%20Motors.htm
Be sure to follow the "more info" links, there are several pages with a fair bit of info and pictures.
6mm reloadable sugar motors:
Now that's really pretty nifty. Something to put away for the future should our everyday motor supply ever dry up
Have to go check my 1/4" 6061-T6 rod stock LOL!!!