They are used for straightening and smoothing long pieces.
The _smooth-plane_, 5-1/2" to 10" long, is a short plane, similar to the jack-plane, except that the cutting edge is straight.

It is used for smoothing.
These four planes, the jack-plane, the fore-plane, the jointer, and the smooth-plane, are essentially alike, and directions for the use of one apply to all.
There are two chief adjustments in the Bailey iron plane: the brass set-screw, see 8 in Fig.

101, which regulates the depth of the cut, and the lever, 9, which moves the cutter sidewise so that it may be made to cut evenly.

The skilful worker keeps constant watch of these adjustments.

It is well to form the habit of always sighting along the sole before beginning to plane, in order to see that the cutter projects properly, Fig.102.It is a common mistake among beginners to let the cutter project too far.
It is important to know what is the best order of procedure in planing up a board.