Method of drilling a workpiece

A method of operating a drill for drilling a workpiece, comprising the steps of:

• initially operating said drill while disengaged from said workpiece, and monitoring the electrical current load on an electric motor operating said drill to establish a no-load value;
• advancing said drill while it is operating to a position in closely spaced relationship to said workpiece at a first, relatively high rate of speed, and thereafter further advancing said drill at a relatively reduced rate of speed so that the drill engages and penetrates the workpiece;
• monitoring the electrical current load on an electric motor operating said drill as it advances through said workpiece;
• discontinuing advancement of the drill when the electrical current load on the electric motor operating the drill drops to a value which is no more than said no-load value, plus a predetermined percentage of said no-load value;
• and
• withdrawing said drill from the workpiece when the electrical current load on the electric motor operating the drill drops to said value at which operation is discontinued.

A method of operating a cutting tool for cutting a workpiece, comprising the steps of:

• initially operating said cutting tool while disengaged from said workpiece, and monitoring the electrical current load on an electric motor operating said cutting tool to establish a no-load value;
• advancing said cutting tool while it is operating so that it engages and penetrates the workpiece;
• monitoring the electrical current load on said cutting tool as it advances through said workpiece;
• and
• discontinuing advancement of the cutting tool when the electrical current load on the cutting tool drops to a value which is no more than said no-load value, plus a predetermined percentage of said no-load value;
• and
• withdrawing said cutting tool from the workpiece when the electrical current load on the cutting tool drops to said value at which operation is discontinued.