I am making a screw-tip powder horn and I have a problem. The screw-tip is stuck part way on and I can't budge it. It did not go on tight. It just won't come back off. I have tried water, soap, heat, and even WD-40. It is not all the way on, so, I can't leave it. Any suggestions would be appreciated. I don't know if this makes any difference, but I lubed the threads with lard when cutting them this time. In the past, I used tap free. The lard seemed to work better.