Quick hunt in the farm field nets a Matron LC, dandy button and pretty sure I know what the other thing is. Though not sure if its 18th century or more modern. Let me know what you think.
That tool is called a roulette. Mine is smaller with sharp teeth. I use it to lay out carving designs on wood. One that size could be used for marking leather or...pies! Gary
My Father in Law use to make custom knives. He used a tool like that on the leather sheathes that he made for those knives. Then again, maybe he borrowed it from my Mother in Law's kitchen drawer, because she was always making pies ! My vote is it's a tool for Leather.