Hi anyone has exprienced lapping of large hone (8x17"). I was given an old hone by my aunt who had it from her father who was involved in national stone mining business. It looks slate ish however I could be surprised due to background of the original owner. I do not want to just experiment with this hone. I do have stone plate large enough to accommodate sanding belts from floor sander however they do not come in higher grits. Anybody can chip in. Many thanks.