A chassis for mounting a set of operating components of a power head of a surgical instrument is disclosed. The power head has a housing enabling access to an interior volume of the power head encompassed by the housing. The set of operating components have a proper configuration for alignment when mounted within the interior volume encompassed by the housing. The chassis is configured to provide the proper configuration for alignment of either an original or replacement set of operating components mounted on the chassis if the chassis and set of operating components are mounted within the interior volume of the housing. The chassis may be formed from metal and the housing formed from a polymer. The chassis may be configured to ground at least one electrical component.