This 28BYJ-48 stepper motor arm with ball drive is product of an exploratory route of the development of a Delta Rotational Robot design you find in the list of my contributions...
I figure it may have some application, and since it is parametric with included generational sources (FreeCAD parametric history modification related features are still unstable, that's why it makes sense to keep versions...) - (early versions might have been too tight on the axis, which may be solved by upping the scale slightly - Its open now - so mix it up!
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