Multi-reel Holder for Mendel90

This design replaces the single-reel holder for the Mendel90. There are two mirrored halves that sit on top of the gantry that hold a .5" (13mm) rod between them.

The right piece also acts as a spacer for the Melzi board (replaces the two small white ring spacers). This allows for the piece to be secured to the gantry. The left piece also has screw clearance holes allowing it to be secured to the left gantry, but I chose not to secure it at this time.

I'm currently using a .5" steel rod th