Just Killing Time, by Julianne Holmes

Ruth Clagan is a clockmaker and expert on clocks.  She just inherited the Cog and Sprocket shop in Orchard, Mass., from her estranged grandfather. Living above the shop puts her in the path of the person who murdered Grandpa Thom.  She has no choice but to figure out who did it.  First in a series that I hope goes on for quite a while.