I wanted to make some of the lithophane lamps here:

https://www.printables.com/model/225160-lithophane-lamp

using the lamp holders I purchase from here:

https://www.amazon.com/dp/B07Z2PNNTG

but they only come with half the number of nuts needed if using 2 per lamp as I did with these lamps. So I designed a replacement nut.