You're absolutely on the money, Bill. I don't know if this is the origin of the phrase (I suspect not, as it seems such an obvious image of a slow abrasive process) but Dickens' character Mr Gradgrind comes to mind...

http://www.doceo.co.uk/background/gradgrind.htm

Perhaps Hard Times could join your reading list if you are enjoying Dickens just now? ~ tho' I must admit I never liked it but!