This is designed for a 6mmx9mm magnet. My magnet measures 5.85mm OD x 9.73mm thick. I have 3 different outside diameters, 40mm, 50mm & 70mm. You can either glue the magnet in place or change the fusion 360 file for a press fit if it does not fit tight on your magnet.
Fusion 360 source of the 50mm diameter version is included.
The author hasn't provided the model origin yet.