Tool is used to close and set the gap to a desired dimension on automotive style spark plugs. Remove the spark plug holder, from main body. Insert spark plug into the recessed end on spark plug holder, with spark plug; in holder replace assemble back into main body, with spark plug electrode resting in steel push block with ground strap on spark plug pointing upwards. Gently turn knurled knob with screw clockwise to take up all slack in main body. With spark plug in man body and electrode facing upwards insert desired thickness feeler gauge between ground strap and electrode. Turn knurled knob with screw clockwise tighten until feeler gauge is snug between the ground strap and the electrode, now the gap is set to the feeler gauge thickness. Turn knurled knob with screw counterclockwise to release pressure on spark plug holder now remove the spark plug holder from main body with spark plug. When removed from main body remove spark plug from spark plug holder and setting the gap is completed.
