A gang drilling machine for drilling a circuit card includes a pair of n and p master drills that are configured to be aligned in registry with respective n and p test vias of the card; pluralities of n and p minion drills that are configured to be aligned in registry with pluralities of n and p live vias of the card; and a controller that is electrically connected to control the n and p master drills and minion drills, and to send and receive electrical signals to and from the card. The controller is configured to: send a query signal to the card; monitor a response signal from the card; determine drilling depth of at least one of the master drills, in response to comparing the response signal to the query signal; and adjust operation of the machine, in response to the determined drilling depth.