Abstract: A milling tool for cutting internally of a bore by means of replaceable bits. The tool comprises an elongate bar member an end portion of which includes a pair of axially outer portions which extend radially outwardly from a central portion and are disposed on respectively opposite sides of the rotational axis. A pair of clamping members are detachably attached to the bar member on respectively opposite sides of the rotational axis and have axially outer portions which together with the axially outer portions of the bar member form an axially outer surface of the tool. The axially outer portions of the bar member and the clamping members cooperate to form four slots in the tool axially outer surface for clamping engagement of radially extending bits.