Spool holder for large filament spools

This is a fairly simple spool holder for the large 300m spools with 3mm filament. The design is similar to many other holders, but this one was made using a CNC milled sandwich plate for the sides and M8 threaded rods to keep everything together.

If you don't have access to a CNC machine, the sides can also be printed in plastic or maybe lasercut in plywood or even acrylic.