This is a model I have made to fix the problem we are having at our home. We are using a drying rack that mounts to the radiator, but our radiators are older types with big spacing between the ribs, and it is challenging to set it correctly. Thus I have replaced the original feet with this one.

I recommend printing in PETG, ASA/ABS, or other types of filament that can withstand heat from the radiator and not deform.

For the infill, it is recommended to use cubic to have more structural rigidity.