Abstract: A method of operating a drill, or like cutting tool, facilitates efficient operation when drilling structural steel components, or like workpieces, which typically exhibit dimensional variations. Instead of controlling drill operations by the specific degree of advancement of the drill, the present invention contemplates that the drill is initially operated, while disengaged from the workpiece, to establish a no-load value of operation. Thereafter, the drill is advanced into the workpiece while it is operating to engage and penetrate the workpiece, while the load on the electric motor operating the drill is monitored. Advancement of the drill is discontinued, and the drill withdrawn, when the load on the drill drops to a value which is no more than the no-load value, plus a predetermined percentage thereof. Efficient operation is desirably promoted, since the drill can be efficiently repositioned when hole formation is complete.

Abstract: A unique system and process for controlling the stroke positions of tools on a multi-station metal working machine are disclosed. The system and process are suitable for use with a metal working machine which carries the tools on an arm pivoted by an actuator. In the preferred embodiment, the control system includes a control circuit which continuously senses the position of the arm by use of a pulse generator rotary encoder. The control system stores settable initial and final stroke positions for each of the tools. The actuator is controlled to move the arm and the tools carried thereon.