Step 1: Drill a Hole in the Metal

Drill a hole in the metal slightly smaller than the diameter of the tap. Apply lubricating oil to the metal as you drill to keep the metal from overheating. Wear safety goggles and long sleeves when drilling for protection from flying chips of metal.

Step 2: Clamp the Piece

Clamp the metal work piece in a vise.

Attach the tap wrench to the top of the tap. Apply lubricating oil to the tap's threads.

Step 3: Insert and Rotate the Tap

Insert the lubricated tap into the hole in the metal, placing it perpendicular to the metal.

Turn the tap wrench clockwise to rotate the tap. For the first few turns, exert moderate downward pressure. Once the first threads have been cut, pressure is no longer needed. After each turn, back the tap out a bit, remove burrs from the edge of the hole, and add more lubricant to the tap to keep it from breaking off in the hole.