No problem. I just realized that you can print the thread of the spool directly instead of making a thin wall and use the nut. I have measured it and I think it is M30×1,5. I managed to print M4 thread so I think it is possible to print this. Creating thread with Fusion 360 is rather easy. You just make a hole of in this case 30mm and create a thread. Don't forget to check the modeled box. I think this will look better and the whole profile can be made thicker.