This was originally modeled in Onshape, then imported to Tinkercad for the lettering portion.  My boss asked me to make this model for my work's Emergency preparedness program.  I have yet to print it, but if it works correctly, the arm ballasts should be sized for US nickels to fit into, and the center hub takes a standard 608 bearing.  (i'm a little fuzzy, loading original onshape files into tinkercad throws off the sizing.)

I'll try and print one this weekend to verify.