The present invention relates to a rotor comprising a rotary housing and at least one oscillating arm, said oscillating arm comprising at least an internal part connected to the housing and an external part carrying tools, one of the parts comprising an engaging portion able to engage partially in an engaged portion of the other part, the said portions each comprising at least one hole and being able to be assembled by means of a connecting device comprising at least one threaded element with a shoulder, said threaded element passing through each hole of the said portions. According to the invention, the connecting device comprises an insert with at least one tapping able to be inserted inside the engaging portion, the threaded element is screwed in the tapping and the shoulder rests on the engaged portion to tighten the engaged portion against the engaging portion.
