Chair Caster Mounting Block For PC Dolly (F3D Customizable)

Have you thought whether a broken caster tuns the entire set into waste? Give the four remaining ones a second chance instead of sending the to landfill. I have tried to find a model that fits my need but all I found is bottom mounted and lifts the platform higher thus making it less stable. My design is meant to be lower to the ground for stability and for clearance (for airflow) above. It is designed for use with casters that have a shaft with 11mm diameter and 22mm length for JUSK chair casters and 10mm X 22mm for IKEA ones.