A toolholder has a head region, which contains a slot separating the head region into a lower section and an upper section, with a lower seat and an upper section to retain a cutting insert. The head region contains a coolant entrance passage, which receives coolant from a coolant source, and a coolant delivery passage, which discharges coolant toward a cutting insert. The head region further contains a fastener bore, which receives a fastener. The fastener has an axial fastener bore which provides fluid communication between the coolant entrance passage and a coolant reservoir between the fastener and the fastener bore. The coolant delivery passage communicates with the coolant reservoir to receive coolant, which passed from the coolant entrance passage and through the axial fastener bore into the coolant reservoir.