Hi. I have a Rogers hi-hat and there is a nylon (plastic?) sleeve with a washer type bottom that sits on the top of the hi-hat. This piece has separated with the sleeve portion moving freely up and down the thin metal tube on the top of the hi-hat while the washer type piece remains imbedded on the top of the hi-hat (see pictures). I do not believe this is supposed to happen. Does anyone know the "official" part name for this and where a replacement can be obtained? All assistance greatfully appreciated. Thanks in advance!!