Abstract: This invention relates to a rotary cutting tool and holder wherein the holder comprises an elongated shank having an internal channel and a conical seat at one end adapted to receive a rotary cutting tool; and a thru pin adapted to fit within the channel. In position, a threaded end of the thru pin projects within the conical seat for attachment of the rotary cutting tool. The attachment end of the rotary cutting tool is conical in shape and designed to fit conformably into the conical seat of the holder. An internal bore through the thru pin and cutting tool permits the transmission of coolant/lubricant to outlets in the cutting head of the cutting tool. The cutting tool is easily removed and replaced for maintenance or other purposes.