These tools are now very extensively used for producing all sorts of flat surfaces on metals. The general form is that, where the work is fixed and supported on a horizontal, moving, cast-iron table, which slides laterally on a frame having two "V" grooves, and is propelled by means of a rack and pinion. Another make of machine, much preferred by some engineers, has its table driven by a screw. The amount of stroke or travel of the plane may be changed to suit the length of the work, by moving two horns fixed on the edge of the table. Some machines are supplied with cone pulleys like a lathe, but many have only one speed, and may be driven direct from the main driving shaft. The power is conveyed by belt pulleys, three being needed; those on the right and left are the driving ones, whereas that in the centre is an idle or slack pulley, on which the belt must be placed when it is desired to stop the machine. The shifting of the belt is effected by a setter, moved by the two horns on the side of the table, or, if necessary, by hand. The tool is generally provided with an automatic feed-motion in three different directions, transverse, vertical, and oblique, which, combined with the motion of the table, will produce horizontal, perpendicular, and slanting surfaces. The feed-motion may be reversed by the movement of a pawl to right or left, and the amount of feed may be changed by altering the relative position of the feed connecting-bar ends on the bell crank levers. One peculiarity about the planing machine is its quick return motion - which is provided to save time during the idle return stroke - the cut being only taken off in one direction. This is accomplished by means of gearing.

The work is fixed on the table, either by bolts and plates, or by the use of a parallel jawed vice. To accommodate different sizes of work, the toolholder may be moved bodily in a vertical direction by two equally pitched screws, connected by a shaft and mitre pinions. The tools used are the same as those employed in the turning lathes, and in consequence the same rules and precautions will be necessary.