Considering the LIMITED context you have revealed, I would suggest that the "round shave" is a steel bladed tool, not unlike a draw knife, used by coopers, barnwrights and wheelwrights to create curved surfaces in wood, such as needed for making slats for a barrel. The word "seythes" quite likely is a phonetic rendering of the word "scythes" and a "fanmill" is a device with a mechanical advantage used to move air for winnowing.