[Fig. 3225] represents a mortising machine for the hubs of wheels.
The auger spindle is here fed vertically by a hand lever, the depth bored being regulated by a rod against which the hand lever comes when the hole is bored to the required depth.
Fig. 3226.
[Fig. 3226] represents a mortising machine in which the mortising tool consists of a hollow square chisel containing an auger, and having at its sides openings through which the cuttings escape.
The chisel is rectangular in cross section, but its cutting edges are highest at the corners, as may be clearly seen in the figure.
The work is firmly clamped to the work table and simultaneously to the fence, the upper hand wheel being operated to bring the work-holding clamp down to the work, and the lower one to clamp it so as to press it to both the table and the fence at the same time.
The chisel bar is mounted horizontally in a slide way on a substantial bed that is mounted on a vertical slideway, which enables the chisel bar to be set for height from the work table. It has a horizontal traverse motion or feed, the amount of this motion being governed by the horizontal rod with its nuts and check nuts as shown.
The auger runs continuously, and works slightly in advance of the cutting edge of the chisel, which is passive except when making the mortise.