Fig. 1870.
Fig. 1871.
The threading head at h (right-hand end of [Fig. 1868]), is represented in [Fig. 1870], being pivoted so that it also can be swung out of the way to permit of the removal of the pipe. The dies c are opened or closed by the hand wheel b, operating a worm meshing into a segment of a worm-wheel upon the body of the head, the amount of motion being regulated by the stop screw at f, which therefore regulates the size to which the dies can be closed, and therefore the diameter of thread the dies will cut. The construction of the cutting-off head is shown in [Fig. 1871], t representing the cutting tool which is operated by the hand wheel k. The carriage is fed or traversed by means of two pinions operated by the six-handled wheel shown at w, [Fig. 1868]; these two pinions engaging racks beneath the carriage, and near the inside edges of the bed, one of them being seen at the extreme right-hand end of [Fig. 1868].
Fig. 1872.
In [Fig. 1872] is represented a machine for threading or tapping the fittings for steam and gas pipe. The tap is carried in the end of the vertical spindle, and the work may be held in the vice upon the work table, or if too large the table may be swung out of the way.
The general design of the machine corresponds somewhat to that of a drilling machine.