Cutting apparatus for a microtunnelling system

The present disclosure relates to a microtunnelling apparatus including a cutting apparatus adapted to be rotated by a drill shaft defining a central axis of rotation that extends along a length of the drill shaft. The cutting apparatus includes a front cutting rotor having a hub defining a shaft receiver that extends at least partially through the hub in a direction extending from a back side toward a front cutting side of the front cutting rotor. The shaft receiver is configured to receive the drill shaft. The drill shaft and the shaft receiver cooperate to define a torque transmitting mechanical interface for allowing torque to be transferred between the drill shaft and the front cutting rotor such that the drill shaft can be used to rotate the front cutting rotor about the central axis of rotation. The front cutting rotor also includes a plurality of cutting bars that project at least partially radially outwardly from the hub. The cutting apparatus further includes a front retainer that mounts at the front cutting side of the front cutting rotor for retaining the front cutting rotor on the drill shaft.