Figure 4-25.-Electric motor-driven carriage being used to cut a circle in steel plate.

The rack is a part of the special torch. The torch also can be tilted for bevel cuts. This machine comes with a straight two-groove track and has a radial bar for use in cutting circles and arcs. A motor-driven cutting torch cutting a circle is shown in figure 4-25. The carriage is

Figure 4-26.-Electric motor-driven carriage being used on straight track to cut a beveled edge on steel plate.

equipped with an off-and-on switch, a reversing switch, a clutch, and a speed-adjusting dial that is calibrated in feet per minute.

Figure 4-26 shows an electric drive carriage on a straight track being used for plate beveling. The operator must ensure that the electric cord and gas hoses do not become entangled on anything during the cutting operation. The best way to check for hose, electric cord, and torch clearance is to freewheel the carriage the full length of the track by hand.

You will find that the torch carriage is a valuable asset during deployment. This is especially true if your shop is called upon to produce a number of identical parts in quantity. Such an assignment might involve the fabrication of a large supply of handhole covers for runway fixtures, or another assignment might be the production of a large quantity of thick base plates for vertical columns. When using the torch carriage, you should lay the track in a straight line along a line parallel to the edge of the plate you are going to cut. Next, you light the torch and adjust the flame for the metal you are cutting. Move the carriage so the torch flame preheats the edge of the plate and then open the cutting oxygen valve and turn on the carriage motor. The machine begins moving along the track and continues to cut automatically until the end of the cut is reached. When the cut is complete,