Hello, I'm new to this kind of access to information. I am refurbishing a few machines that have been in my basement for years. Ice review is up and running but I would like to replace the rollover discs at the roll over exits on left and right of table ( see picture). My problem is I do not know their diameter. difficult to measure fixed and do not want to remove as I will no doubt damage them. Anybody done this job and knows what size they are?