Before the time of woodworking machines, such as we have to-day, it was customary to surface or plane the broad surfaces by hand, as will be described later in this chapter. To-day, woodworkers may go to any lumber yard and get stock, machine planed upon the two broad surfaces to stock thicknesses. Such surfaces are sufficiently smooth or level and the thicknesses sufficiently uniform for much woodwork, especially in carpentry, so that the process of squaring up the stock, which means making the edges, surfaces, and ends at right angles to a face side or a face edge, is greatly simplified.

Fig. 45. Surfacing Machine

Fig. 45. Surfacing Machine.

Fig. 45 is an illustration of a machine used to plane broad surfaces of boards. This machine has long knives attached to a revolving cylinder extending across the bed. As the board is made to travel over the bed by an automatic feed, these knives, revolving at a speed of 3,500 to 3,800 revolutions per minute, remove chips entirely across the board. Where the board is fed over the table slowly, thus giving the knives plenty of time for action on a given place, it is difficult for a beginner to tell a machine planed board from one that is hand planed. The little ridges and hollows across the machine planed board are there, however, and must be removed with the hand plane, where a stain or filler is to be applied later. If this is not done, every ridge and hollow will be made to stand out prominently when the stain is applied.