You would have to give Gene or Tom a call to find out exactly what is or isn't ground. All I can say is that if it isn't a slide-way then it doesn't really need to be ground. I don't really know for sure what you are referring to tho as "bottom supporting ways" ? Generally speaking if it is a "way" then it has a slide feature. If it is "supporting" then it is a static structure, and may not even require machining at all.