A ground breaking machine has a housing and the housing has oppositely disposed end plates which have aligned axial female openings and matching male plate portions positioned in the female openings. The female opening is defined by a side edge having top and oppositely disposed vertical spaced apart side edge portions. Each of the vertical side edge portions terminate in a laterally inwardly extending portion having an upperwardly extending hook portion engageable with a downwardly extending hook portion on the male plate portion for interlocking the female and male hook portions to prevent separation thereof and separation of the male plate portion in the female opening.The method of assembly and mounting the cutter drum in the housing includes the steps of providing a housing having oppositely disposed end plates including aligned axial openings and matching male plate portions for being positioned in the female openings. The cutter drum has a gear drive mounted in an end of the cutter drum and is provided with a hydraulic motor on one of the male plate portions. The cutter drum is positioned under the housing and the male plate portion having the hydraulic motor is positioned in the female opening in an end plate. The hydraulic motor on the male plate portion is connected to the gear drive in the end of the cutter drum.