This is my knowhow idea for backless studs. This stud earring doesn't need back. It is just spiral, which you need just twist to put it on.
Can be 3D printed in Gold, Platinum or Silver.
Please, watch my short video instruction on my youtube channel: https://www.youtube.com/watch?v=i7rLg7zDC9A
Production takes 2-3 weeks.