Internal Threads

[bardd]

Recently I've been thinking of the possible applications of internal threading in building the robot. I think it may help lower the robot's overall weight, losing the weight of nuts, and it would be much easier to assemble, being able to use only one hand and having no nuts to drop.
The thing is, I have no idea how to make them without spending a week preparing them.

What do you think the advantages or disadvantages of internal threads?

Also, did any of you ever use internal threading and has some insights about making and using them?