Wheel hub for plywood.

I made triangular ones but decided to go to 5 arms for more strength. Use one on each side of your plywood disks. These are for 8mm rod axles.

Experiment with your extruder nozzle diameter setting to get good bonding. (I'm currently slicing and printing from Slic3R to SD card.)

the arms are 1.5mm thick so aim for a nozzle setting that's just under or a size with a multiple just under. Check your slicing output to see how well the circular paths bond at intersections.