I am sure this issue has been discussed but can't find it so I am posting this question. I have a double roller grain mill they had a black rubber o-ring on one of the rollers. Somehow it broke off and now my mill doesn't work very well. It keeps jamming and not rolling at all, feels like it is slipping as the crank will turn but rollers will not. Anyone have a fix for this? Do I buy a new o-ring if they sell them, if it is even possible to take a roller off and replace the o-ring?