I'm trying to make earrings out of some small items I have. I don't know what kind of plastic some of them are, but very firm so heating up the post doesn't work. I have tried drilling a hole, but the bits are too small for a drill, and the adapter I bought is not working well either. I bought a hand drill as well, but I am too impatient and have too weak of hands for that to be practical. Another material I'm working with is plaster that I've cast into a mold. For that I was thinking maybe I could insert the post to the plaster when it is still wet, but would have to figure out how to get it to the right height and level.

Any advice on making earrings out of difficult materials in general would be helpful.