2 Words to use with reversing

Singer Co. (PWH); 14Jan69; R454086. Instructions for using Singer Electric sewing machines 99-23 and 99-24 lock stitch for family use, adjustable reverse feed for tacking.

Though the engineer seemed to be taking it easily enough with his hand resting lightly on the reversing-lever, his body at rest, the fireman was kept on the jump.

2 Words to use with  reversing