I have been pouring for a few years and have a question. I have a problem with my shakey heads the head wiggles on the hook shank after a little use. I use pure soft lead as I can get all I will ever use free, could this bee the problem? I remove them pretty quick after pouring could this cause the problem? My supply is running low and it's time to pour again just trying to get some things to try to solve this problem before I start. Thanks