The file '3508 Motor Mount For .5 Inch Dowels 3D Printer Model' is (stl) file type, size is 27.0KB.
I remixed this design to be able to fit over 1/2" pine dowels used on my Flitetest Electrohub. They fit great and seem like they'll be quite strong. They use a standard 25mm x 25mm mounting hole spacing.