Smoothing planes are used for the finest finishing work on the wood surface. Before sandpaper was in common use, surfaces such as veneers were not sanded down but smoothed with the smoothing plane. It was essential to set the iron with extreme precision and to work with the highest degree of skill.

Planes with mouth adjustment are known as reform smoothing planes. An adjustable plate in the sole of the plane permits the mouth to be reduced in size, either for particularly fine work or at the stage when the sole of the plane has been worn and has had to be trimmed.

As with all planes, it is very important to get to know a new plane, and sharpening it will rapidly deepen the acquaintance. Even if there is a note in the box to say a new plane is sharpened and ready for use, you should really take the time to sharpen and hone a new plane.